Moscow
Standartinform
3. APPROVED AND INTRODUCED BY Order federal agency on technical regulation and metrology of October 26, 2005 No. 264-st
4. This standard implements the provisions of the Law Russian Federation"On Ensuring the Uniformity of Measurements" and the Law of the Russian Federation "On Technical Regulation"
5. INTRODUCED FOR THE FIRST TIME
Information about changes to this standard is published in the annually published information index "National Standards", and the text of changes and amendments - in monthly published information signs "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly published information index "National Standards". Relevant information, notification and texts are also placed in the information system common use- on the official website of the national body of the Russian Federation for standardization on the Internet
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1 area of use. 2 3. Terms and definitions. 3 4. General provisions. 5 5. Development of a method for quantitative chemical analysis of water samples. 5 6. Certification of the method of quantitative chemical analysis of water samples. 7 Appendix A. Standards for the presentation of accuracy indicators (correctness and precision) of the method of quantitative chemical analysis of water samples. eight Appendix B. Basic concepts and representation of uncertainty. nine Appendix B. Methods for assessing the accuracy indicators (correctness and precision) of the method of quantitative chemical analysis of water samples. ten Appendix D. Construction, content and presentation of documents regulating the methods of quantitative chemical analysis of water samples. 12 Appendix E. Examples of the design of sections of documents regulating the methods of quantitative chemical analysis of water samples. fourteen Appendix E. Content of work in the course of metrological studies and certification of the method of quantitative chemical analysis of water samples. 17 Appendix G. Form of certificate of attestation of the method of quantitative chemical analysis of water samples. eighteen Bibliography. nineteen |
GOST R 8.613-2005
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
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State system ensuring the uniformity of measurements TECHNIQUES FOR QUANTITATIVE CHEMICAL ANALYSIS OF WATER SAMPLES General requirements to the development State system for ensuring the uniformity of measurements. |
Introduction date - 2006-07-01
1 area of use
This standard applies to newly developed and revised methods for the quantitative chemical analysis of samples of natural, drinking, waste water (hereinafter referred to as the MCCA of water samples) and establishes general requirements for their development and certification.
2. Regulatory references
This standard uses Normative references to the following standards:
GOST R 1.5-2004 Standardization in the Russian Federation. National standards of the Russian Federation. Rules for construction, presentation, design and designation
GOST R 8.563-96 State system for ensuring the uniformity of measurements. Measurement techniques
GOST R ISO 5725-1-2002 Accuracy (correctness and precision) of measurement methods and results. Part 1. Basic provisions and definitions
GOST R ISO 5725-2-2002 Accuracy (correctness and precision) of measurement methods and results. Part 2: Basic method for determining repeatability and reproducibility standard method measurements
GOST R ISO 5725-3-2002 Accuracy (correctness and precision) of measurement methods and results. Part 3. Intermediate precision values of the standard measurement method
GOST R ISO 5725-4-2002 Accuracy (correctness and precision) of measurement methods and results. Part 4: Basic methods for determining the validity of a standard measurement method
GOST R ISO 5725-5-2002 Accuracy (correctness and precision) of measurement methods and results. Part 5 Alternative Methods determining the precision of a standard measurement method
GOST R ISO 5725-6-2002 Accuracy (correctness and precision) of measurement methods and results. Part 6. Using precision values in practice
GOST 1.2-97 Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. The order of development, adoption, application, updating and cancellation
GOST 8.315-97 State system for ensuring the uniformity of measurements. Standard Samples composition and properties of substances and materials. Key points
GOST 8.417-2002 State system for ensuring the uniformity of measurements. Units
GOST 27384-2002 Water. Standards of measurement error of indicators of composition and properties
Note - When using this standard, it is advisable to check the validity of reference standards in the public information system - on the official website of the national body of the Russian Federation for standardization on the Internet or according to the annually published information index "National Standards", which was published as of January 1 of the current year, and according to the corresponding monthly published information signs published in the current year. If the reference standard is replaced (modified), then when using this standard, you should be guided by the replaced (modified) standard. If the referenced standard is canceled without replacement, the provision in which the reference to it is given applies to the extent that this reference is not affected.
3. Terms and definitions
In this standard, the following terms are used with their respective definitions:
3.7. quantitative chemical analysis of water samples: Experimental quantitative determination of the content of one or a number of components of the composition of a water sample by chemical, physicochemical, physical methods (taking into account the recommendations).
3.8. result of a single analysis (determination): The value of the content of a component in a water sample, obtained during a single implementation of the analysis procedure.
3.9. analysis result (measurement): Medium arithmetic value or the median of the results of a single analysis (determination) (taking into account the recommendations).
3.10. method of quantitative chemical analysis of samples of natural, drinking, sewage, treated wastewater; MKCA of water samples: A set of operations and rules, the implementation of which provides the results of a quantitative chemical analysis of samples of natural, drinking, sewage, treated wastewater with established error (uncertainty) characteristics (taking into account recommendations).
Note - MCCA of water samples is a kind of measurement technique.
3.11. quality indicators of MKCA water samples: Indicators of accuracy (correctness and precision) of the MKCA of water samples.
3.12. indicators of accuracy (correctness and precision) of MKCA of water samples: Assigned characteristics of the error (its components) of the MCCA of water samples (taking into account the recommendations).
3.13. assigned characteristics of the MKCA error of water samples and the characteristics of the error of its components: The established characteristics of the error and its components for any of the totality of the results of the analysis obtained in compliance with the requirements and rules of the certified ICCA water samples (taking into account the recommendations).
Note - The assigned error characteristics characterize the guaranteed accuracy of the MKCA of water samples.
3.14. measurement uncertainty: A parameter associated with a measurement result that characterizes the spread of values that can be attributed to the measurand .
NOTE Uncertainty is the equivalent of an assigned error characteristic. In this case, the equivalent of the expanded uncertainty is the interval estimate of the assigned error characteristic, the equivalent of the standard uncertainty is the point estimate of the assigned error characteristic [see. Table A.1 (Appendix A) and Appendix B].
3.15. content range (measurement range): The interval of the content of the indicator of a water sample, provided for by the ICCA of water samples.
3.16. Scope of MKCA water samples: The range of contents and ranges of permissible values of the influencing factors of water samples and MCCA of water samples.
3.17. influencing factors of water sample: Interfering components and other properties (factors) of the sample that affect the result and the error (uncertainty) of measurements.
3.18. influencing factors of MCCA of water samples: Factors, the values of which determine the conditions for the analysis of water samples according to the ICCA and which affect the result and the error (uncertainty) of measurements.
4. General provisions
4.1. The MCCA of water samples is developed and used in order to ensure the performance of measurements with an error (uncertainty) that does not exceed the standard of measurement error for indicators of the composition and properties of water, established by GOST 27384.
4.2. The ICCA of water samples is set out in the following documents:
National standards of the Russian Federation;
Standards of organizations (enterprises).
4.3. MKCA water samples are used:
Organs state control for pollution and the state of the natural environment;
Bodies of state sanitary supervision;
Organs public service monitoring the level of environmental pollution;
Organizations, individual enterprises or groups of enterprises (related to the relevant industry, department or association of legal entities) to assess the quality and (or) pollution of water.
4.4. Standards for MCCA of water samples (hereinafter referred to as documents for MCCA of water samples) are developed in accordance with the requirements of GOST R 1.5, GOST 1.2 and GOST R 8.563. Metrological supervision of water samples certified by the MKCA is carried out in accordance with GOST R 8.563 and,.
5. Development of a method for quantitative chemical analysis of water samples
5.1. The development of ICCA water samples consists of the following stages:
Development of terms of reference (TOR);
Choice of the method of analysis and technical means (measuring instruments, standard samples, certified mixtures, reagents and materials, volumetric utensils, equipment);
Establishing the sequence and content of operations in the preparation and performance of measurements, including the establishment of influencing factors of water samples and MCCA of water samples and methods for their elimination, the range of contents of the determined component and the permissible values of influencing factors;
Experimental testing of the established algorithm for performing measurements (carrying out pilot measurements);
Planning and conducting an experiment (metrological studies) to assess the quality indicators of the ICCA of water samples to establish the attributed characteristics of the measurement error (uncertainty) and its components;
Establishment of the values of the assigned characteristic of the error (uncertainty) of measurements;
Selection and assignment of algorithms operational control analysis procedures for the implementation of the ICCA of water samples in a particular laboratory;
Development of a draft document for the ICCA of water samples;
MKCA certification of water samples;
Approval of the draft document for the ICCA of water samples.
5.2. The ToR contains the initial data for the development of the ICCA of water samples (names of the measured quantities, characteristics of the analyzed water samples, measurement errors of indicators of the composition and properties of water samples, measurement conditions in the form of nominal values and (or) range boundaries possible values influencing quantities).
5.3. Methods and measuring instruments are chosen in accordance with. The types of measuring instruments chosen must be approved in accordance with:
Rules, if the MKCA of water samples is intended for use in the field of distribution of state metrological control and supervision;
The procedure established in the field of defense and security, if the ICCA of water samples is intended for use in the field of defense and security.
Standard samples must be approved in accordance with GOST 8.315, certified mixtures must be approved in accordance with.
5.4. For the MKCA of water samples used to measure the component at the level of the water quality standard, when establishing the range of component contents, the lower limit of the range of contents of the determined component With n must satisfy the condition
With n? 0.5NKV, (1)
where NKV is the water quality standard.
Notes
1. An exception may be components for which it is impossible to achieve the values indicated in formula (1). In this case With n can satisfy the condition With n? NKV.
2. In the absence of data on the value of the NKV, data on the background or average levels of the values of this indicator are used as an indicative level of values for the water quality component.
5.5. The planning of an experiment to assess the quality indicators of the MKCA of water samples is carried out in accordance with GOST R ISO 5725-1, GOST R ISO 5725-2, GOST R ISO 5725-4 and.
In general, the main stages of planning an experiment to assess the quality indicators of the MCCA of water samples are:
Drawing up a block diagram of the ICCA of water samples and analysis of possible sources of error (uncertainty) of measurements;
Studying the composition of initial water samples, studying the possible influence of the total composition of water samples on the measurement results;
Refinement of the range and scope of the ICCA of water samples based on the study;
Selection of the method for assessing the quality indicators of the MCCA of water samples based on the study, determining the availability of standard samples, the possibility of preparing certified mixtures, adding additives to the analyzed sample, the availability of a comparison method, etc.;
Determination of the number of laboratories that should be involved in a joint assessment experiment (if necessary, the introduction of ICCA water samples into the network of laboratories);
Determining the timing of the evaluation experiment.
5.6. Methods for expressing the attributed error characteristics of the MKCA of water samples must comply with the recommendations, taking into account Annex A and the requirements of GOST R ISO 5725-1. Uncertainty is expressed in accordance with , , and taking into account Annex B.
The methods for assessing the quality indicators of the MKCA of water samples are selected according to GOST R ISO 5725-1, GOST R ISO 5725-2, GOST R ISO 5725-4, GOST R ISO 5725-5, and also in accordance with the recommendations and Appendix B. Methods for assessing uncertainty choose according to , , .
5.7. The choice and assignment of algorithms for operational control of the analysis procedure during the implementation of the ICA of water samples in a particular laboratory is carried out in accordance with. The choice and assignment of algorithms for monitoring the stability of the measurement results obtained by the MKCA of water samples when it is implemented in a particular laboratory is carried out in accordance with GOST R ISO 5725-6 and.
5.8. Documents for the ICCA of water samples in the general case should contain the following sections:
Purpose and scope of ICCA water samples;
Assigned characteristics of measurement error (uncertainty);
Measuring instruments, auxiliary devices, reagents, materials;
Measurement method;
Requirements for the qualification of performers;
Measurement conditions;
Preparation for measurements;
Performing measurements;
Calculation of measurement results, including methods for checking the acceptability of single determination results obtained under repeatability conditions and measurement results obtained under reproducibility conditions;
Quality control of measurement results during the implementation of the MKCA of water samples in the laboratory;
Registration of measurement results.
The construction and presentation of documents for the ICCA of water samples - in accordance with Appendix D. Examples of the design of some sections of the documents for the ICCA of water samples are given in Appendix D.
6. Certification of the method of quantitative chemical analysis of water samples
6.1. Certification of the ICCA of water samples is carried out in order to confirm the possibility of performing measurements in accordance with the procedure regulated by the document for the ICCA of water samples, with measurement error (uncertainty) characteristics that do not exceed the assigned error (uncertainty) characteristics specified in the document for the ICCA of water samples.
6.2. Water samples are certified by the MKCA:
State Scientific and Metrological Centers (GNMC);
Bodies of the State Metrological Service (OGMS);
32 State Research and Testing Institute (hereinafter referred to as 32 GNIII MO RF) (in the field of defense and security);
Metrological services (organizational structures) of an organization (enterprise).
Metrological service ( organizational structure) organizations (enterprises) that carry out certification of the ICCA of water samples, used in the field of distribution of state metrological control and supervision, must be accredited for the right to certify the ICCA of water samples in accordance with the rules.
Note - Documents for the ICCA of water samples used in the areas of distribution of state metrological control and supervision are subjected to metrological examination at the SSMC or in organizations whose metrological services are accredited for the right to conduct metrological examination of documents for the ICCA of water samples used in the areas of distribution of state metrological control and supervision. Documents for the MKCA of water samples intended for use in the field of defense and security are subject to metrological examination at the 32nd State Research Institute of the Ministry of Defense of the Russian Federation. Metrological examination of documents for the MKCA of water samples is not carried out if the certification of the MKCA of water samples is performed by one of the GNMC or 32 GNIII MO RF.
6.3. Certification of the MKCA of water samples is carried out by metrological examination the following materials for the development of ICCA water samples:
ToR for the development of ICCA water samples;
Draft document regulating the ICCA of water samples;
Programs and results of experimental and computational evaluation of quality indicators of the ICCA of water samples.
6.4. When conducting studies to establish the quality indicators of the ICCA of water samples, as well as during its certification, the performance of the work listed in Appendix E should be provided.
6.5. When conducting a metrological examination of materials for the development of the ICCA of water samples, they analyze the compliance of the methods for presenting the quality indicators of the ICCA of water samples with the main provisions of GOST R ISO 5725-1 - GOST R ISO 5725-4, recommendations and Appendix C (methods for presenting uncertainty to recommendations,, and Appendix B ); in terms of quality control procedures for the measurement results, they analyze and note in the expert opinion the use of procedures in accordance with GOST R ISO 5725-6 and. When conducting a metrological examination of documents for the ICCA of water samples, recommendations and are used.
6.6. At positive results attestations:
Issue a certificate of attestation of the MKCA of water samples (except for the MKCA of water samples regulated by national standards). The form of the certificate is given in Appendix G. The procedure for registering certificates of certification of the ICCA of water samples is established by organizations (enterprises) that carry out the certification of the ICCA of water samples;
The document regulating the ICCA of water samples is approved in the prescribed manner;
In the document regulating the ICCA of water samples (except for state standard), indicate: "methodology certified" - with the designation of the organization (enterprise), the metrological service of which carried out the certification, or the GNMC, or the OGMS, which performed the certification of the MKCA of water samples.
Annex A
(reference)
Forms of presentation of indicators of accuracy (correctness and precision) of the method of quantitative chemical analysis of water samples
Table A.1
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Name of the quality indicator of the ICCA water samples |
Form of presentation of the quality indicator of the ICCA water samples |
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Accuracy indicator of MCCA of water samples - assigned error characteristic of MCCA of water samples |
1. The boundaries [lower, upper (D n, D c)], in which the error of any of the totality of the results of the analysis (measurements) is found with the accepted probability R,- interval estimation, or ±D, R, for D = |D n | =D in = Z s(D), where Z- distribution quantile, depending on its type and accepted probability R. 2. Standard deviation - s(D) of the error in the results of analysis (measurements) obtained in all laboratories using this ICCA of water samples - point estimate |
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The indicator of the correctness of the MCCA of water samples is the assigned characteristic of the systematic error of the MCCA of water samples |
where? is the mathematical expectation (estimate) of the systematic error; s c - standard deviation of the non-excluded systematic error of the MCCA of water samples - point estimate. Note - ? can be introduced into the result of a single analysis (determination) as a correction. 2. Boundaries (D s, n, D s, c), in which the systematic error of the MCCA of water samples is found with the accepted probability R, - interval estimate, or ± D s, R, where D s,v = |D s,n | =D with = Zs c |
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The indicator of the repeatability of the MCCA of water samples is the assigned characteristic of the random error of the results of a single analysis obtained under conditions of repeatability |
1. Standard deviation of the results of a single analysis obtained under repeatability conditions (results of parallel determinations) - s r . 2. Repeatability limit - r for two single analysis results obtained under repeatability conditions (results of parallel determinations) |
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The reproducibility indicator of the MKCA of water samples is the assigned characteristic of the random error of the results of analysis (measurements) obtained under conditions of reproducibility |
1. Standard deviation of the results of analysis (measurements) obtained under reproducibility conditions - s R. 2. Reproducibility limit - R for two analysis results (measurements) |
NOTE If the MCCA of water samples is being developed for use in a single laboratory, the assigned error characteristics of the MCCA of water samples are: accuracy score, intralaboratory precision score, repeatability score, and correctness score (laboratory bias). Presentation forms - in accordance with .
Annex B
(reference)
Basic concepts and representation of uncertainty
B.1. The uncertainty of the result of the analysis (measurements), expressed as the standard deviation, is the standard uncertainty and .
B.2. The method for estimating uncertainty by statistical analysis of series of observations is a type A estimate.
B.3. A method for estimating uncertainty, other than statistical analysis of series of observations, is a type B estimate.
B.4. The standard uncertainty of a measurement result, when the result is obtained from the values of a number of other quantities, equal to the positive square root of the sum of the terms, the terms being the variances or covariances of these other quantities, weighted according to how the measurement result changes with changes in these quantities, is total standard uncertainty .
B.5. A quantity that defines the interval around a measurement result within which (one might expect) most of the distributions of values that could reasonably be attributed to the measurand is the expanded uncertainty.
B.6. The numerical factor used as a multiplier of the combined standard uncertainty to obtain the expanded uncertainty is the coverage factor. The coverage rate is usually between 2 and 3. Acceptance of the coverage rate k= 2 gives an interval that has a confidence level of approximately 95%, and acceptance k= 3 gives an interval having a confidence level of approximately 99%.
B.7. In accordance with when calculating the uncertainty, the result of the analysis (measurements) - X must be specified together with the expanded uncertainty u, which is calculated using the coverage factor k= 2. The following form is recommended:
X ± U, (B.1)
where U is the expanded uncertainty, calculated using a coverage factor of 2, giving a confidence level of approximately 95%.
Methods for assessing accuracy indicators (correctness and precision) of the method of quantitative chemical analysis of water samples
IN 1. In general, the MCCA of water samples includes the following stages:
Sample preparation for analysis;
Direct measurements of analytical signals (intermediate measurements) and their processing;
Calculation of the result of measurements of the value of the indicator of the composition (properties) of waters, functionally related to the results of direct measurements.
Each of these operations is burdened with its own errors. Many factors can influence the formation of the error of the measurement result, including:
Random differences between the compositions of the samples taken;
Matrix effects and mutual influences;
Incomplete extraction, concentration;
Possible changes in the composition of the sample due to its storage;
Errors of the measuring instruments used, including standard samples (RM) or certified mixtures (AC), equipment, as well as the purity of the reagents used;
Inadequacy of the mathematical model underlying the measurement method to the physical phenomenon;
Inadequacy of samples for calibration to the analyzed samples;
Uncertainty of the blank correction value;
Operator actions;
Variations in environmental parameters during measurements (temperature, humidity, air pollution, etc.);
Random effects, etc.
IN 2. The assessment of the values of the assigned error characteristic - an indicator of the accuracy of the MCCA of water samples - is carried out according to the established values of the characteristics of its random and systematic components in the entire range of contents of the determined component, for all ranges of associated components (hereinafter referred to as the influencing factors of the sample), as well as the conditions for performing measurements given in document for ICCA water samples.
IN 3. The assessment of precision indicators (repeatability and reproducibility) can be carried out on homogeneous and stable working water samples using either RM for the composition of water according to GOST 8.315, or AC according to the basis of an interlaboratory experiment. The results of the analysis of the same samples or SS (AS) are obtained with random variations of the influencing factors of the methodology under reproducibility conditions ( different time, different analysts, different batches of reagents of the same type, different sets of volumetric utensils, different copies of measuring instruments of the same type, different laboratories).
Note - Working samples should be homogeneous and stable in composition throughout the duration of the experiment.
AT 4. The assessment of the indicator of correctness of the MCCA of water samples can be carried out in one of the following ways - using:
A set of samples for evaluation (ES) in the form of CO or AS;
The additive method and the additive method combined with the dilution method;
Certified methodology with known (estimated) measurement error characteristics (comparison methods);
Calculation method (by summing the numerical values of the components of the systematic measurement error).
B.4.1. The use of a set of samples for evaluation in the form of CO or AC in the conditions of obtaining experimental data in several laboratories allows you to evaluate the constant part of the systematic error, as well as the variable part of the systematic error due to the influencing factors of the sample. General composition The TOE must comply with the scope of the ICCA for water samples. The content of the indicator to be determined and the levels of interfering factors of the sample in the TOE are selected in accordance with the requirements of the experimental design (single-factor or multi-factor).
B.4.2. The use of the additive method in combination with the dilution method makes it possible to estimate the additive (constant) and multiplicative (proportionately changing) parts of the systematic error of the MCCA of water samples. The use of the additive method makes it possible to estimate the multiplicative (proportionately changing) part of the systematic error of the MCCA of water samples. The use of the additive method is permissible if at the stage of preliminary studies or according to a priori data it is established that the additive (constant) part of the systematic error is not a statistically significant fraction of the error of the analysis result.
Samples for evaluation are working water samples, working water samples with a known additive, diluted working samples and diluted working samples with a known additive.
Note - The use of the addition method and the addition method in combination with the dilution method is acceptable if at the stage of preliminary studies or according to a priori data it is established that the influencing factors of the sample do not have a significant effect on the error of the analysis result.
B.4.3. The use of a method based on the use of certified ICCA water samples with known (estimated) error characteristics (hereinafter referred to as ICCA comparison) is possible under the following conditions:
The scope of the MCCA of comparison coincides with the scope of the investigated MCCA of water samples or overlaps it;
The value of the reproducibility indicator of the MCCA of comparison does not exceed the value of the reproducibility indicator of the investigated MCCA of water samples;
The systematic error of the MKCA comparison is insignificant against the background of its random error;
MKCA comparison meets the requirements of intralaboratory control of the accuracy of its results.
Note - The use of MCCA comparison is acceptable if at the stage of preliminary studies or according to a priori data it is established that the influencing factors of the sample do not have a significant effect on the error of the analysis result.
B.4.4. The application of the calculation method is based on the summation of the numerical values of the components of the systematic error.
In the calculation method, the factors that form the systematic error of the MCCA of water samples can include all the factors listed in B.1, with the exception of random effects, the quantitative assessment of the influence of which is taken into account when calculating the standard deviation of the results of a single analysis (determination) obtained in repeatability conditions.
Construction, content and presentation of documents regulating the methods of quantitative chemical analysis of water samples
D.1. The name of the document for the MKCA of water samples must comply with the requirements of GOST R 1.5 and GOST R 8.563.
D.2. The document for the ICCA of water samples must contain an introductory part and sections arranged in the sequence:
Norms of measurement error;
Method of analysis (measurements);
Measuring instruments, auxiliary devices, reagents and materials;
Safety requirements, environmental protection;
Operator qualification requirements;
Conditions for performing analysis (measurements);
Preparation for analysis (measurements);
Performing analysis (measurements);
It is allowed to exclude and (or) combine some sections.
D.3. In the introductory part, the purpose and scope of the ICCA of water samples should be established. The types of analyzed waters, the name of the analyzed component, the range of contents of the analyzed component and the ranges of variations of the influencing factors of the sample allowed by the ICCA of water samples should be indicated. If necessary, information on the duration and complexity of measurements can be given.
The first paragraph of the introductory part is stated as follows: “This document (indicate specifically the type of document for the ICCA of water samples) establishes a method for quantitative chemical analysis of water samples (indicates the types of analyzed waters) to determine in them (hereinafter - the name of the measured quantity, indicating the range of measured component and measurement method used)”.
D.4. The section "Norms of measurement error" should contain the permissible values of the accuracy index, characterizing the required measurement accuracy. Measurement error rates are indicated in accordance with GOST 27384 for the entire range of measured contents of the analyte.
D.5. The section "Ascribed characteristics of the measurement error and its components" contains the numerical values of the quality indicators of the MKCA of water samples. Methods for expressing the quality indicators of the ICCA water samples should comply with Appendix B and recommendations.
The values of the assigned characteristics of the measurement error (the quality indicators of the ICCA of water samples) must be indicated for the entire range of measured contents. If the quality indicators of the MCCA of water samples depend on the measured content, their values should be presented in the form of a functional dependence on the measured content or a table of values by content intervals, within each of which changes in the values of the quality indicators can be neglected.
Note - If the section gives the values of uncertainty, then the methods of its expression are presented in accordance with and .
D.6. The section "Measurement method" should contain the name of the measurement method and a description of the principle (physical, physico-chemical, chemical) underlying it.
D.7. The section "Measuring instruments, auxiliary devices, reagents, materials" should contain a complete list of measuring instruments (including standard samples), auxiliary devices, materials and reagents needed to perform measurements. In the list of these means, along with the name, indicate the designations of national standards (standards of other categories) or technical specifications, designations of types (models) of measuring instruments, their metrological characteristics (accuracy class, limits of permissible errors, measurement limits, etc.).
If the measurement requires special devices, devices, in help application drawings, descriptions and characteristics of water samples should be brought to the document for ICCA of water samples.
D.8. The section "Requirements for safety, environmental protection" contains requirements, the fulfillment of which ensures labor safety, industrial sanitation standards and environmental protection when performing measurements.
D.9. The section "Requirements for the qualification of the operator" should include requirements for the level of qualification (profession, education, work experience, etc.) of persons allowed to perform measurements.
D.10. The section “Conditions for performing measurements” should contain a list of factors (temperature, pressure, humidity, etc.) that determine the conditions for performing measurements, the ranges of changes in these factors allowed by the ICAA of water samples or their nominal values, indicating the limits of permissible deviations.
D.11. The section "Preparation for measurements" should contain a description of all the preparations for measurements.
The section should describe the stage of checking the operating modes of the measuring equipment and bringing it into working condition, or give a link to regulatory documents that establish the procedure for preparing the equipment used.
The section should describe the methods of processing the analyzed samples of samples for calibration, the procedures for preparing solutions necessary for analysis. For solutions with limited stability, the conditions and periods of their storage should be indicated. It is allowed to give the method of preparation of solutions in the reference appendix to the document for the ICCA of water samples.
If the establishment of a calibration characteristic is provided for when performing measurements, the section should provide methods for its establishment and control, as well as the procedure for using samples for calibration.
If, in order to establish the calibration characteristic, it is necessary to use calibration samples in the form of mixtures prepared directly during measurements, the section should contain a description of the procedure for their preparation, the values (one or more) of the contents of the components of the mixture of initial substances and the characteristics of their errors.
It is allowed to give the method of preparation of such samples in the reference appendix to the document for the ICCA of water samples.
If the procedure for preparatory work is established by documents for measuring instruments and other technical means, then the section provides links to these documents.
D.12. In the "Performance of measurements" section, the requirements for the volume (mass) of sample portions, their number, methods of taking an analytical portion should be established, if necessary, an instruction is given to conduct a "blank experiment"; the sequence of carrying out and the content of operations that provide the measurement result, including operations to eliminate the influence of interfering sample components, if any, are determined.
D.13. In the section “Processing (calculation) of the measurement result”, methods for calculating the value of the content of the indicator in the analyzed water sample from the obtained experimental data should be described. Calculation formulas for obtaining the measurement result must be given with the indication of the units of the measured values in accordance with GOST 8.417.
This section provides methods for checking the acceptability of the results of parallel determinations obtained under repeatability conditions and measurement results obtained under reproducibility conditions.
The numerical values of the measurement result must end with a digit of the same digit as the value of the accuracy index of the MKCA of water samples.
D.14. The section "Formation of measurement results" contains requirements for the form of presentation of the obtained measurement results.
D.15. The section “Quality control of measurement results when implementing the methodology in the laboratory” should contain a description of control procedures, values of control standards, requirements for control samples.
Annex D
(reference)
Examples of the design of sections of documents regulating the methods of quantitative chemical analysis of water samples
D.1. In accordance with Appendix A, this appendix provides examples of the design of the introductory part and the following sections of documents for the ICCA of water samples:
Assigned characteristics of measurement error and its components;
Processing (calculation) of the result of analysis (measurements);
Registration of analysis results (measurements);
Quality control of the results of analysis (measurements) during the implementation of the methodology in the laboratory.
D 2. An example of the design of the introductory part
“This standard of an organization (enterprise) establishes a methodology for the quantitative chemical analysis of wastewater samples to determine in them mass concentration sulfate ions from 25 to 400 mg / dm 3 by the gravimetric method.
D.3. An example of the design of the section "Ascribed characteristics of the measurement error and its components"
E.3.1. The method of quantitative chemical analysis provides the results of analysis (measurements) with an error, the value of which does not exceed the values indicated in Table E.1.
Table E.1 - Measurement range, values of indicators of accuracy, repeatability and reproducibility of the MCCA of water samples
E.3.2. The values of the accuracy index of the MKCA of water samples are used for:
Registration of the results of analysis (measurements) issued by the laboratory;
Evaluation of the activities of laboratories for the quality of testing;
Assessing the possibility of using the results of analysis (measurements) in the implementation of the ICA of water samples in a particular laboratory.
D.4. An example of the design of the section "Processing (calculation) of the result of analysis (measurements)"
E.4.1. The result of a single analysis (determination) - the content of the determined indicator in the sample is found according to the calibration curve.
E.4.2. The result of the analysis (measurements) of the content of the determined indicator in the sample is taken as the arithmetic mean of the results of two parallel determinations obtained under repeatability conditions, the discrepancy between which should not exceed the repeatability limit. Repeatability limit values r for two results of parallel determinations are indicated in Table E.2.
When the repeatability limit is exceeded r need to get more n (n? 1) results of parallel determinations. If, in this case, the discrepancy ( X max- X min) results 2 + n parallel definitions less than (or equal to) the critical range CR 0.95 (2+ n) according to GOST R ISO 5725-6, then the arithmetic mean of the results 2 + n parallel definitions. Critical range values for 2+ n the results of parallel determinations are indicated in Table E.2.
If the discrepancy ( X max- X min) more CR 0.95 (2+ n), as the final result of the analysis (measurement) take the median 2 + n results of parallel determinations.
Upon receipt of two consecutive results of analysis (measurements) in the form of a median, the reasons for the occurrence of such a situation are found out and operational control of the analysis procedure is carried out in accordance with .
Table E.2 - Measurement range, values of the repeatability limit and the critical range at the assumed probability R = 0,95
E.4.3. The discrepancy between the results of the analysis (measurements) obtained in two laboratories should not exceed the reproducibility limit. If this condition is met, both results of the analysis (measurements) are acceptable and their total average value can be used as the final result. The values of the reproducibility limit are indicated in Table E.3.
If the reproducibility limit is exceeded, methods for assessing the acceptability of the results of analysis (measurements) can be used in accordance with Section 5 of GOST R ISO 5725-6.
Table E.3 - Measurement range, values of the reproducibility limit at the accepted probability R = 0,95
D.5. An example of the design of the section "Formatting the results of analysis (measurements)"
The result of the analysis (measurements), , in documents providing for its use, can be represented in the form
where - the result of the analysis (measurements), obtained in accordance with the prescription of the methodology;
D is an indicator of the accuracy of the MKCA of water samples. The values of D are given in section E.3 "Assigned characteristics of the measurement error and its components".
It is permissible to present the result of analysis (measurements) in the documents issued by the laboratory in the form
provided D l< D,
where ± D l - the value of the measurement results error characteristic, established during the implementation of the methodology in the laboratory, in accordance with the procedure adopted in the laboratory, taking into account the recommendations and ensured by monitoring the stability of the measurement results.
Note - When presenting the result of the analysis (measurements) in the documents issued by the laboratory, indicate the number of results of parallel determinations performed to obtain the result of the analysis (measurements), and the method of calculating the result of the analysis (measurements) - the arithmetic mean or median of the results of parallel determinations.
D.6. An example of the design of the section "Quality control of the results of analysis (measurements) when implementing the methodology in the laboratory"
D.6.1. Quality control of the results of analysis (measurements) when implementing the methodology in the laboratory provides for:
Operational control of the analysis procedure (measurements) - based on the assessment of the error in the implementation of a single control procedure;
Control of the stability of the measurement results - based on the control of the stability of the standard deviation of repeatability, the standard deviation of intralaboratory precision, error.
E.6.2. Algorithm for operational control of the analysis procedure (measurements) using control samples (CO or AS)
K to with control standard K.
K k is calculated by the formula
where - the result of the control measurement of the content of the analyte in the control sample - the arithmetic mean of two results of parallel determinations, the discrepancy between which does not exceed the repeatability limit r. Meaning r indicate in table D.2;
With- certified value of the control sample.
Control standard K calculated according to the formula
K= D l, (D.2)
where ±D l - characteristic of the error of the measurement results, corresponding to the certified value of the control sample and set according to .
Kto ? K.(D.3)
If condition (D.3) is not met, the experiment is repeated. If the condition (D.3) is not met again, the analysis process is suspended, the reasons leading to unsatisfactory results are found out, and measures are taken to eliminate them.
D.6.3. Algorithm for operational control of the analysis procedure (measurements) using the method of additions
Operational control of the analysis procedure (measurements) is carried out by comparing the result of a single control procedure K to with control standard K d .
The result of the control procedure K k is calculated by the formula
(D.4)
where - the result of a control measurement of the content of the analyte in a sample with a known additive - the arithmetic mean of two results of parallel determinations, the discrepancy between which does not exceed the repeatability limit r. Meaning r indicate in table D.2;
The result of the control measurement of the content of the determined component in the working sample is the arithmetic mean value n results of parallel determinations, the discrepancy between which does not exceed the repeatability limit r;
With- additive.
Control standard K d is calculated by the formula
(D.5)
where are the values of the error characteristic of the results of analysis (measurements) established in the laboratory when implementing the methodology, corresponding to the content of the analyte in the working sample and in the sample with the additive.
The procedure of analysis (measurements) is recognized as satisfactory if the condition is met
K to? K d . (D.6)
If condition (E.6) is not met, the experiment is repeated. If the condition (D.6) is not met again, the analysis process is suspended, the reasons leading to unsatisfactory results are clarified, and measures are taken to eliminate them.
The frequency of control of the analysis procedure (measurements), as well as the implemented procedures for monitoring the stability of the results of analysis (measurements) are established in the Laboratory Quality Manual.
Appendix E
(reference)
The content of work in the course of metrological studies and certification of the method of quantitative chemical analysis of water samples
Table E.1
|
Name of works |
Executor |
|
1. Checking the availability of the conditions necessary for the metrological studies of the MKCA of water samples: Verification of the compliance of the draft document, which regulates the ICCA of water samples, submitted for metrological certification, with the requirements of the ToR and Appendix D of this standard; Checking the correctness of the choice of measuring instruments provided for by the ICCA of water samples; Verification of compliance with the conditions for the use of measuring instruments provided for by the ICCA of water samples, the conditions for their use specified in normative documents on measuring instruments; Availability check, technical condition and compliance with the requirements of the ICCA of water samples of measuring instruments, auxiliary equipment, laboratory glassware, reagents, materials necessary for certification of water samples by the ICCA; Checking the compliance of the methods for preparing mixtures required for certification of the ICCA of water samples with the recommendations |
|
|
2. Drawing up a program for the experimental and computational evaluation of the quality indicators of the ICCA of water samples |
Developer of the MKCA of water samples, metrological service of the organization (enterprise), GNMC, OGMS |
|
3. Carrying out research to establish the values of quality indicators of the ICCA of water samples to assess the values of the assigned error characteristic and its components, formalizing the results of the research |
Developer of ICCA water samples |
|
4. Validation: Carrying out studies to establish quality indicators of the MKCA water samples; Establishing the values of quality indicators of the ICCA water samples; The choice (calculation) of the norms of measurement error for the determined component of the composition (properties) of water. Verification of the compliance of the calculated values of the assigned characteristic of the measurement error with the standards of measurement error. Analysis of the validity of procedures and standards for quality control of measurement results in the implementation of the IQCA of water samples in the laboratory |
Developer of the MKCA of water samples, metrological service of the organization (enterprise), GNMC, OGMS |
|
5. Certification of water samples by the ICCA based on the results of the metrological examination of materials for its development, including materials for establishing quality indicators, in accordance with the recommendations |
Organization that certifies the MKCA of water samples [metrological service of the organization (enterprise), GNMC, OGMS] |
|
Form of certificate of attestation of the method of quantitative chemical analysis of water samples name of the organization (enterprise) that carried out the certification of the MKCA water samples CERTIFICATE No. Method for quantitative chemical analysis of water samples ________________________________________________________________________ name of the measured quantity, measurement method, types of water developed by ____________________________________________________________ name of the organization (enterprise) that developed the ICCA of water samples and regulated by _____________________________________________________ designation and name of the document certified in accordance with GOST R 8.563-96. Certification was carried out based on the results of _____________________________________ type of work: metrological examination of materials for the development ________________________________________________________________________ MCCA of water samples, theoretical or experimental study of MCCA of water samples, other types of work The results of certification of the MKCA of water samples that meet the metrological requirements for it are given in tables G.1 and G.2 (with the accepted probability P = 0,95). Table G.1 Table G.2 When implementing the MKCA, water samples in the laboratory provide: Operational control of the analysis procedure (based on the assessment of the error in the implementation of a single control procedure); Control of the stability of the results of the analysis (based on the control of the stability of the standard deviation of repeatability, the standard deviation of intralaboratory precision, error). The algorithm for operational control of the analysis procedure is given in the document for the ICCA of water samples. Procedures for monitoring the stability of the results of the analysis are established in the Quality Manual of the laboratory. date of issue Head of organization (enterprise) _________________ __________________ personal signature signature transcript Place of printing |
Bibliography
|
State system for ensuring the uniformity of measurements. Indicators of accuracy, correctness, precision of methods of quantitative chemical analysis. Assessment methods. - M.: IPK Publishing house of standards, 2004 |
|
|
International dictionary of terms in metrology VIM (Russian-English-German-Spanish Dictionary of basic and general terms in metrology). - M.: IPK Publishing house of standards, 1998 |
|
|
PR 50.2.002-94 |
State system for ensuring the uniformity of measurements. The procedure for exercising state metrological supervision over the release, condition and use of measuring instruments, certified methods for performing measurements, standards and compliance with metrological rules and norms. - M.: VNIIMS, 1994 |
|
State system for ensuring the uniformity of measurements. Metrological control and supervision carried out by the metrological services of legal entities. - M.: VNIIMS, 1994 |
|
|
State system for ensuring the uniformity of measurements. The choice of methods and means of measurement in the development of methods for performing measurements. General provisions. - M.: VNIIMS, 1989 |
|
|
PR 50.2.009-94 |
State system for ensuring the uniformity of measurements. The procedure for testing and approval of the type of measuring instruments (with Amendment No. 1). - M.: VNIIMS, 1994 |
|
State system for ensuring the uniformity of measurements. Blends certified. General requirements for development. - M.: IPK Publishing house of standards, 2004 |
|
|
State system for ensuring the uniformity of measurements. Results and characteristics of measurement errors. Presentation forms. Methods of use in testing product samples and monitoring their parameters. - M.: VNIIMS, 2004 |
|
|
State system for ensuring the uniformity of measurements. Application of the "Guidelines for the Expression of Uncertainty in Measurement". - M.: IPK Publishing house of standards, 2001 |
|
|
Guidance on the expression of measurement uncertainty. - Per. from English. - S.-Pb.: VNIIM im. DI. Mendeleev, 1999 |
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|
EURACHIM/SITAC Manual//Quantitative description of uncertainty in analytical measurements. - 2nd ed., 2000. - Per. from English. - S.-Pb.: VNIIM im. DI. Mendeleev, 2002 |
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|
State system for ensuring the uniformity of measurements. Internal control the quality of the results of quantitative chemical analysis. - Yekaterinburg: UNIIM, 2002 |
|
|
PR 50.2.013-97 |
State system for ensuring the uniformity of measurements. The procedure for accreditation of metrological services of legal entities for the right to attest methods for performing measurements and conducting metrological examination of documents. - M.: VNIIMS, 1997 |
|
State system for ensuring the uniformity of measurements. Ensuring the effectiveness of measurements in management technological processes. Estimation of measurement error with limited initial information. - M.: IPK Publishing house of standards, 2004 |
|
|
R 50.2.008-2001 |
State system for ensuring the uniformity of measurements. Methods of quantitative chemical analysis. The content and procedure for the metrological examination. - M.: IPK Publishing house of standards, 2001 |
Keywords: methodology for quantitative chemical analysis of samples of natural, drinking, waste waters (MCCA of water samples), measurement error standards, attributed characteristics of measurement errors, quality indicators of MCCA of water samples
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Chemical Methods Method No. 113-X
TIN
Industry methodology Category III accuracy
(Version 2009)
Moscow, 2009
MINISTRY OF NATURAL RESOURCES AND ECOLOGY OF THE RUSSIAN FEDERATION
FEDERAL SCIENTIFIC AND METHODOLOGICAL CENTER FOR LABORATORY STUDIES AND CERTIFICATION OF MINERAL RAW MATERIALS "VIMS"
Scientific Council for Analytical Methods
Chemical methods Method 113-X
TIN
QUANTITATIVE CHEMICAL ANALYSIS METHOD
PHOTOMETRIC DETERMINATION OF TIN IN ROCKS, ORES, AND MINERALS WITH phenylfluorone after co-precipitation with beryllium hydroxide
Industry methodology 111 accuracy categories
(Version 2009)
Moscow, 2009
X - the amount of tin found according to the calibration curve, μg,
V is the total volume of the test solution, cm ';
A is the volume of an aliquot of the test solution taken for determination, cm 1;
H - hitch, g.
If the mass fraction of tin must be converted to absolutely dry matter,
the result obtained (in%) is multiplied by the value -, where a is the content
hygroscopic water (in %), determined by drying a separate portion of the sample at 105°C.
11.2. The result of measuring the tin content in the sample is taken as the arithmetic mean of two results of parallel determinations, the discrepancy between which should not exceed the repeatability limit. The values of the repeatability limit (r) for two results of parallel determinations are given in Table 2.
11J. The discrepancies between the results of the analysis (measurements) obtained in two laboratories, ns should not exceed the reproducibility limit L = 2.&7 *. If the absolute difference between the results of two measurements does not exceed R, these measurements are considered consistent, and their arithmetic mean can be used as the final result. The values of the reproducibility limit are indicated in Table 2. If the reproducibility limit R is exceeded, find out the reasons for this excess (GOST R ISO 5725-6, section 5.3).
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table 2 Measurement range, values of repeatability and reproducibility limits at a confidence level Р=0.95 |
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12. REGISTRATION OF THE RESULTS OF THE ANALYSIS (MEASUREMENTS)
The result of the analysis (measurements) in the documents providing for its use is presented as:
ChiL, R- 0.95,
where x is the result of analysis (measurements), expressed as a mass fraction of the element being determined (%),
D is an indicator of the accuracy of the applied method of quantitative chemical analysis.
The values of L are given in Table 1. The numerical value of the analysis result must end with a digit of the same digit as the value of the error characteristic.
13. QUALITY CONTROL OF THE RESULTS OF THE ANALYSIS
13.1. Quality control of the measurement results when implementing the methodology in the laboratory provides for:
Operational control by the executor of the measurement procedure based on the assessment of the error in the performance of a single control procedure;
Monitoring the stability of measurement results based on monitoring the stability of the standard deviation of repeatability and the standard deviation of intralaboratory precision.
13.2. Algorithm for operational control of the analysis procedure using
samples for control.
Operational control of the measurement procedure is carried out by comparing the result of a single control procedure K k with the accuracy control standard K.
The result of the control procedure K to (in mass fractions,%) is calculated by
formula: K k \u003d jx-C |,
where X is the result of measuring the content of the analyte in the control sample (in mass fractions, %);
C - certified value of the determined component in the control sample (in mass fractions, %).
The accuracy control standard is calculated by the formula:
K = D, /> = 0.95,
where D is an indicator of the accuracy of the measurement results corresponding to the certified value of the control sample C.
The D values are given in Table I.
The accuracy of the control measurement is considered satisfactory if:
K k £ K and unsatisfactory if K k > K.
If the condition K to< К эксперимент повторяют. При повторном невыполнении условия, процесс анализа приостанавливают, выясняют причины, приводящие к неудовлетворительным результатам, и принимают меры по их устранению.
It is acceptable to present the result of the analysis (measurements) in the documents issued by the laboratory in the form:
x and D, P - 0.95, subject to D,< Д.
where Dn is the value of the measurement results error characteristic, established during the implementation of the methodology in the laboratory, in accordance with the procedure adopted in the laboratory, and ensured by monitoring the stability of the measurement results.
LITERATURE
1. Ginzburg L.B., Shkrobot E.P. Determination of small amounts of tin in ores by fluorescent and colorimetric methods. Head Lab. 23, 5, 527 (1957).
2. Safety instructions for laboratory work, M.VIEMS, 1976.
3. Nazarenko V.A., Lebedeva N.V. Determination of tin in poor ores with paranitrophenylfluorone. Head Lab. 23, 3,268, 1962.
4. Nazarenko V.A., Lebedeva N.V. Derivatives of trioxyfluorone as reagents for tin and antimony. JAH, X, 5, 289, 1955.
5. Nazarenko V.A., Lebedeva N.V. Ravitskaya R.V. Methods for determining germanium in ores, coals and industrial wastes. Head Lab. 24.1, 9, 1958.
6. Sakaki Takashi. On the determination of tin in iron and steel by the spectrophotometric method. Ref. Zhur. Chemistry, 23, G 133, 1966 (Nihon Konzoku Gakkaishi. J. Japan Inst. Metals 29, Jfe 9, 835, 1965)
7. Seidel E. Colorimetric methods for determining traces of metals. Ed. "Mir", M., 1964, p. 774.
8. Silaeva E.V., Kurbatova V.N. Determination of tin in ferromolybdenum. Head Lab. 27.12, 1462 (1961).
9. Charlot G. Quantitative analysis of inorganic compounds. Ed. "Chemistry", M., 1965, p. 754.
10. Shumova T.I., Blum I.A. Determination of low tin content with butylrhodamine S. Head. Lab. 34, 6, 1968.
11. Bcnnct R.L., Smith H.A. Spectrophotometric determination of tin with phcnylfluorone. Analyt. Chem. 31, 8.1441, 1959.
12. Luke C.L. Photometric determination of tin with phcnylfluorone. Analyt. Chem. 28, 8, 1276, 1956.
1. PURPOSE AND SCOPE OF THE METHOD
This document establishes a methodology for the quantitative chemical analysis of rocks, ores and minerals to determine in them photometric method mass fraction tin in the range from 0.02 to 1.5%.
2. CHARACTERISTICS OF MEASUREMENT ERROR
The limits of the relative total error of the result of measurements of the mass fraction of tin in natural objects of various compositions are given in Table 1.
The errors indicated in Table 1 correspond to the requirements for measurement errors established by OST 41-08-212-04 and adopted by the Ministry of Natural Resources of Russia.
Table 1
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Relative total error limits |
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3. MEASURING INSTRUMENTS, AUXILIARY EQUIPMENT, MATERIALS, REAGENTS
When performing measurements, the following measuring instruments, auxiliary equipment, materials and reagents are used.
3.1. Measuring instruments.
Analytical laboratory scales of any type, 1st accuracy class, GOST 24104.
Spectrophotometer or photocolorimeter of any type that measures optical density solutions in the range of 490 - 530 nm.
Dimensional cylinders 1-5 (10, 25, 50. 100), GOST 1770.
3.2. Auxiliary equipment, utensils.
Electric hob with closed spiral and temperature controlled heating, GOST 14419.
Muffle furnace of any type with a heating temperature of 100°C.
3.3. Standard composition samples.
Standard samples of the composition (GSO, OSO, MSO) or certified mixtures (AS) with a certified tin content, established with a certification error that is insignificant compared to the method error (table 1). GSO, OSO, MSO and AS should be similar in composition and content of vanadium to the analyzed samples.
3.4. Reagents and materials.
Hydrofluoric acid, analytical grade, GOST 10484.
Ammonia oxalate, one-water, pure, GOST 5712.
Beryllium sulfate, tetrahydrate salt, (BeS0 4 -4H 2 0), analytical grade, TU 6-09-2561.
Iron trichloride, six-water, analytical grade, GOST 4328.
11 sodium tetraborate, decahydrate (borax), analytical grade, GOST 4199.
Disodium salt of tetraacetic acid, two-water (complexon 111), analytical grade, GOST 10652.
Sodium carbonate, anhydrous (soda), analytical grade, GOST 83.
Tin metal, chemically pure, TU 6-09-2704.
Phenylfluorone, analytical grade, TU 6-09-05-289.
Gelatin.
Indicator P-dinitrophenol,
Indicator paper, universal (pH 1-10), TU 6-09-1181
Litmus paper (indicator), TU 6-09-3403.
Ethyl alcohol, TU 6-09-1710.
Ashless filters "white tape", diameter 9 cm and 7 cm, TU 6-09-1678.
It is allowed to use other types of measuring instruments, utensils, auxiliary equipment, including imported ones, with characteristics not worse than those given in clauses 3.1, 3.2. All reagents used in clause 3.4. must have an analytical purity class (chda or chemically pure).
4. MEASUREMENT METHOD
Tetravalent tin in an acidic medium (0.1-3 N) forms a sparingly soluble complex compound with phenylfluorone. At a low content of tin in the solution, a colloidal suspension is formed, which is stabilized by the addition of a protective colloid - gelatin. The resulting colloidal solution, depending on the tin content, acquires a color from yellow (the color of an acidic solution of phenylfluorone) to red through various shades orange (I, 4, 8, II, 12J.
The maximum light absorption of a solution of a colored complex of tin with phenylfluorone lies in the region of about 500 nm. The molar light absorption coefficient is 80000.
In this version of the method, the reaction takes place in a solution of 0.3 N in sulfuric acid. The color intensity reaches a maximum after two hours and remains constant for several hours.
The optical density of the solution is measured on a photocolorimeter (Xp**=490-530 nm). The color of the solution obeys the Bouguer-Beer law in the range from 2 to 20 μg of tin in 50 cm 3 of the solution.
Fsnilfluoron is not a specific reagent for tin. Germanium (IV), zirconium and hafnium, gallium, antimony (III), molybdenum (VI), tungsten (VI), niobium, tantalum, titanium and iron (III), antimony ( V) ns forms a colored compound with phenylfluorone.
The determination of tin is also hindered by elements whose ions have their own color.
Chromium (VI), vanadium (V), manganese (VII) and nitrate ion interfere with the determination of tin, since they oxidize the reagent, and in this case a color similar to that of tin phenylfluoronate appears.
Fluorine interferes with the determination, as it binds tin into a stronger complex.
Interfering elements are separated by precipitating tin hydroxide together with beryllium hydroxide at pH~9 in the presence of complexone III. Under these conditions, iron, titanium, zirconium, hafnium and other elements bind into strong complex compounds.
Since significant amounts of tetraboric acid pass from the flux into the solution, which prevents the complete precipitation of beryllium and tin hydroxide in the presence of complexone III, sesquioxides are preliminarily precipitated with ammonia without the addition of beryllium and complexone (10). In this case, tungsten and molybdenum are partially separated.
Nitrate ion and fluorine are removed during the decomposition of a test sample sample.
The interfering effect of tantalum (Ta 2 0 5) and niobium (Nb 2 Oj) with their total content of ns more than 1.3 mg in the analyzed sample is eliminated by adding ammonium oxalate to the colorimetric solution, which forms strong complex compounds with the elements (3). The influence of high contents of tantalum and niobium was not tested by the authors.
To decompose the sample, it is treated with sulfuric and hydrofluoric acids, evaporated to dryness, and the dry residue is fused with a mixture of borax and soda. With this method of decomposition, tin is oxidized to four valence, which is required for reaction with phenylfluorone; antimony is oxidized to pentavalent antimony, which does not form a colored compound with phenylfluorone; The crystal acid is removed, and the entire sample (including cassiterite, the most common and sparingly soluble tin mineral) becomes soluble.
5. SAFETY REQUIREMENTS, ENVIRONMENTAL PROTECTION
When performing measurements of the mass fraction of tin, one should observe the safety requirements when working with chemical reagents in accordance with GOST 12.1.007, the electrical safety requirements when working with electrical installations in accordance with GOST 12.1.019. The laboratory premises must comply with fire safety requirements
ambient air temperature, °С 20±5;
Atmosphere pressure, kPa (mm Hg) 101 ±4 (760±30);
relative air humidity, % 65±15;
mains voltage, V 220±22;
AC frequency, Hz 50± I.
8. SAMPLING, PREPARATION AND STORAGE
Sampling is carried out according to the customer's regulatory
documents.
When sampling, an accompanying document is drawn up in the approved form, which indicates:
The purpose of the analysis,
Place, time of selection,
Sample number
■ position, sampler's name, date.
Preparation and storage of samples is carried out in accordance with OST 41-08-249-85.
9. PREPARATION FOR MEASUREMENTS
In preparation for the measurements, the following work is carried out:
9.1. Preparing the device for work.
Preparation of the spectrophotometer or photocolorimeter for operation and optimization of measurement conditions is carried out in accordance with the instructions for use of the instruments. Devices must be verified.
92. Preparation of auxiliary solutions.
9.2.1. Preparation of sulfuric acid solution diluted 1:1.
An equal volume of sulfuric acid is slowly added to the volume of distilled water, cooled, stirred. Shelf life is one year.
92.2. Preparation of a solution of sulfuric acid, diluted 1:3.
One volume of sulfuric acid is slowly added to three volumes of distilled water, cooled, stirred. Shelf life is one year.
922. Preparation of sulfuric acid solution, diluted 1:9.
One volume of sulfuric acid is added to nine volumes of distilled water, cooled, stirred. Shelf life is one year.
92A. Preparation of hydrochloric acid solution, diluted 1:1.
Mix equal volumes of distilled water and hydrochloric acid. Shelf life is one year.
9.2.5. Preparation of hydrochloric acid solution, diluted 1:10.
To ten volumes of distilled water add one volume of hydrochloric acid, cool, mix. Shelf life is one year.
9.2.6. Preparation of ammonia solution diluted 1:1.
Mix equal volumes of distilled water and ammonia. Shelf life is one year.
9.2.7. Preparation of ammonia solution diluted 1:4.
One volume of ammonia is added to four volumes of distilled water. Stir. Shelf life is one year.
92A. Preparation of 25% sodium hydroxide solution.
A portion of sodium hydroxide weighing 25 g is dissolved in distilled water, the volume of the solution is adjusted with distilled water to 100 cm 3 , cooled, stirred. Store in a polyethylene vessel with a screw cap for 1 year. The solution must be transparent.
9.2.9. Preparation of a 4% solution of ammonia oxalate.
Salt weighing 4 g of salt is dissolved in distilled water, the volume of the solution is adjusted with distilled water to 100 cm 3 , stirred. Shelf life is one year.
9.2.10. Preparation of a solution of beryllium sulfate containing - 10 mg Be
A portion of BeS0 4 -4H 2 0 weighing 19.7 g or a portion of BeCl 2 4H 2 0 weighing 16.9 g is dissolved in 20-30 cm 3 of hydrochloric acid and the volume of the solution is adjusted with distilled water to 100 cm 3 . Shelf life is one year.
9.2.11. Preparation of a solution of ferric chloride containing - 10 mg Ke 2 0 * in
A portion of FeCl 3 weighing 2 g is dissolved in 100 cm 3 of hydrochloric acid, diluted 1:10. Shelf life is one goal.
9.2.12. Preparation of a 15% solution of complexon III.
A portion of complexon III weighing 150 g is dissolved in 1 dm 3 of ammonia, diluted 1:4, mixed. Shelf life is one year.
9.2.13. Preparation of a 0.03% solution of phenylfluorone.
A portion of phenylfuorone weighing 0.15 g is dissolved by heating on a water bath in 450 cm 3 of alcohol, to which 2 cm 3 of sulfuric acid 1:1 was previously added. Alcohol is added to the cooled solution to a volume of 500 cm 3, left overnight and filtered.
through a dry filter into a dry flask, discarding the first portions of the filtrate. The shelf life of the solution is one year. The solution must be transparent.
9.2.14. Preparation of a mixture for fusion, consisting of borax and soda in a ratio of 1: 2.
A sample of borax dehydrated at 300-400 ° C is thoroughly ground with soda in a porcelain mortar. The pounded mixture is stirred to obtain a homogeneous mixture in a large glass jar with a ground stopper. Shelf life is one year.
9.2.15. Preparation of 0.5% gelatin solution.
A portion of gelatin weighing 0.5 g is dissolved in 100 cm 3 of distilled water, heated to 60-70°C. The solution is filtered. Use on the day of preparation.
9.2.16. Preparation of 0.1% aqueous solution indicator (Cainitrophenol.
100 mg of the indicator is dissolved in 100 cm 3 of distilled water. Shelf life I
9.3. Preparation of the calibration solution of tin.
9.3.1. Preparation of solution A.
A portion of metallic tin chemically pure weighing 0.1000 g is dissolved when heated in -10 cm 3 sulfuric acid 1:1, evaporated until sulfuric acid vapor appears, the walls of the glass are washed with distilled water and again evaporated to sulfuric acid vapor. The cooled solution is transferred to a 100 cm 3 volumetric flask and topped up to the mark with sulfuric acid diluted 1:3. Shelf life 1 year. The solution must be transparent.
In I cm 3 solution A contains 1000 μg of tin.
9JJ. Preparation of solution B.
10 cm 3 of solution A is placed in a 100 cm 3 volumetric flask and topped up to the mark with sulfuric acid 1:9. Shelf life is five months. The solution must be transparent.
I cm 1 of solution B contains 100 μg of tin.
933. Preparation of solution B.
10 cm 3 of solution B are placed in a 100 cm 3 volumetric flask and topped up to the mark with sulfuric acid 1:9. Shelf life is one month. The solution must be transparent.
1 cm 1 of solution B contains 10 μg of tin.
9.4. Construction of calibration graphs.
In glasses with a capacity of 300 cm 3 placed 2 g of the mixture for fusion, about 40 cm 3 hydrochloric acid 1:1, 1 cm 1 solution of ferric chloride and 0; 2.5; 5.0; 7.5; 10.0; 15.0; 20.0 cm 3 of standard solution B containing 10 μg of tin in 1 cm 3 (0; 25.0; 50.0; 75.0; 100.0; 150.0; 200.0 μg of tin). Metal hydroxides are then precipitated with ammonia and then continue as indicated during the analysis. For photography, 5 cm 3 of each solution (0; 2.5; 5.0; 7.5; 10.0; 15.0; 20.0 µg of tin in a colorimetric volume) are taken and continue as described during the analysis. The optical density is measured after 2 hours but relative to the zero solution on a photocolorimeter in a 20 mm cuvette with a blue-green light filter (X pml = 490-500 nm). The optical density is plotted along the y-axis, and the concentration of tin in 50 cm 3 of the solution is plotted along the abscissa.
9L Control of the stability of the calibration characteristic.
The control of the stability of the calibration characteristics is carried out simultaneously with the measurement of the analyzed solutions. Means of control are prepared solutions for calibration (at least three solutions corresponding in terms of tin concentration approximately to the beginning, middle and end of the calibration curve).
The calibration characteristic is considered stable if the following condition is met for the calibration of each solution:
where C is the result of a control measurement of the mass concentration of tin in the calibration solution;
C, - the value of the mass concentration of tin in the calibration solution;
D is the value of the error characteristic corresponding to the mass concentration of tin in the calibration solution (C c). The values of D are given in table. one.
If the condition for the stability of the calibration characteristic is not met for only one calibration solution, it is necessary to re-measure it in order to eliminate the result containing a gross error.
If the calibration characteristic is not stable, find out the reasons for the instability of the calibration characteristic and repeat the control of its stability using other calibration solutions provided by the procedure. When the instability of the calibration characteristic is detected again, a new dependence is built on a new series of calibration solutions.
10. PERFORMING THE ANALYSIS
When performing measurements of the tin content, the following operations are performed.
10.1. Sample decomposition.
A portion of the analyzed material weighing 0.1-0.5 g is placed in a platinum crucible or in a small platinum cup, 10-15 cm 3 of hydrofluoric acid are added and heated for 1-2 hours. To the residue evaporated to dryness, add 3-4 cm 3 of sulfuric acid 1:1 and heat until thick sulfuric acid fumes appear.
The crucible is allowed to cool, the walls of the crucible (or cup) are washed with cold distilled water, stirred and heated again until the release of sulfuric acid vapors ceases. 2 g of the fusion mixture is added to the dry residue and carefully fused at 900° C. in a muffle furnace. The melt in the crucible (or cup) is distributed by rotational motion in a uniform thin layer along the walls. The cooled crucible with contents is placed in a beaker with a volume of 300 cm 3 , 15-30 cm 3 of distilled water, 20 cm 3 of concentrated hydrochloric acid are added and heated until the alloy dissolves. The crucible is removed from the solution and rinsed thoroughly with distilled water.
10.2. Separation of tin from interfering elements.
Hydrates of mixed oxides are precipitated with ammonia to separate the bulk of the boron that has passed into solution from the flux. To a solution heated to a boil, add
dilute 1:1 ammonia solution until odor appears and an excess of 1-1.5 cm ji . The solution together with the precipitate is left for 10-15 minutes on a warm plate to coagulate the precipitate and filtered through a "white ribbon" filter. The precipitate on the filter is washed several times with hot distilled water with the addition of ammonia. The washed precipitate is thoroughly washed off the filter with hot distilled water into the beaker in which the precipitation was carried out, 20 cm 1 of hydrochloric acid is added to the same beaker, passing hydrochloric acid through the filter. 0.5 cm 3 of a beryllium salt solution, 10 cm 3 of a complexone III solution are added to the solution in a glass and heated to a boil. Ammonia solution 1:1 is added to the hot solution until strong odor and an excess of 5-8 cm 3 to pH=9 (check with universal indicator paper!). Then, 1-2 drops of a beryllium salt solution are added to the solution with a precipitate, vigorously mixed, put for 10 minutes (but not more) for warm tiles to coagulate the precipitate and immediately check the pH of the solution. If the pH is greater or less than 9, either ammonia or hydrochloric acid is added. The solutions are left for 1.5-2 hours for the complete release of beryllium hydroxide. The cold solution is filtered through a "white tape" filter with a diameter of 7 cm, thoroughly washed with distilled water with the addition of ammonia (pH=9) and left on the filter for 30 minutes to drain the water. The washed residue is washed from the expanded filter with hot sulfuric acid diluted 1:9 into the beaker in which precipitation was carried out, and after cooling, transferred with the same acid to a 50 cm 3 volumetric flask.
10.3. Photostring.
For analysis, 5 cm 3 of the solution is taken, placed in a 50 cm 3 volumetric flask (if less than 5 cm 3 was taken, add to 5 cm 3 with sulfuric acid 1: 9), add 3 drops of a solution of the indicator 0-dinntrofsnol and carefully drop by drop 25 % sodium hydroxide solution until the color of the solution changes from colorless to slightly yellow. Then 4 cm 3 of a 4% solution of ammonium oxalate and 4 cm 3 of sulfuric acid 1:9 are added to the solution. After adding each reagent, the solution is stirred. Carefully, along the wall, so as not to mix the solution, add 2 cm 3 of a 0.5% solution of gelatin and immediately 3 cm 3 of a 0.03% solution of phenylfluorone. The solution is stirred, topped up with distilled water to the mark and mixed again.
At the same time, a “zero” solution is prepared: 5 cm 3 of sulfuric acid 1:9 are placed in a 50 cm 3 volumetric flask and all solutions are placed in the same order.
Two hours later, the optical density of the solution is measured on photocolorimstrs at X* id =490-500 nm in a cuvette with a layer thickness of 20 mm in relation to the "zero" solution.
11. PROCESSING (CALCULATION) OF ANALYSIS RESULTS
The calculation of the results of the analysis to determine the tin content is carried out as follows:
11.1 Mass fraction (in%) of tin is calculated by the formula:
1 If at the same time the precipitate does not fall out or falls out in an insignificant amount, add 1 cm * of a solution of ferric chloride
In practice, all the achievements of analytical chemistry as a science are realized in its final product - chemical analysis technique specific object.
There are methods of qualitative chemical analysis and methods of quantitative chemical analysis of the substance of the object of analysis. Qualitative and quantitative chemical analysis procedures can be described sequentially in one method.
Method of chemical analysis substances of the object of analysis - a document in which, in accordance with the method of analysis used, a sequence of operations and rules is described, the implementation of which ensures obtaining chemical analysis result a specific substance of a specific object of analysis with established error characteristics or uncertainty for methods of quantitative analysis, and for methods qualitative analysis- with established reliability.
The result of chemical analysis can be presented, for example, as follows: according to the method of qualitative analysis, by conducting qualitative reactions, it was established that with a 100% certainty there is iron in the sample of the ore substance of the Bakcharskoye deposit; according to the method of quantitative analysis by dichromatometry, it was established that the iron content in the sample of the ore substance of the Bakcharskoe deposit is (40 ± 1)% with a confidence level of 0.95.
Each method of chemical analysis is based on the use of any one method of chemical analysis.
Examples of names of chemical analysis methods:
Method for measuring the mass concentrations of cadmium, copper and lead ions in drinking, natural and sewage stripping voltammetry method .
Methodology for performing measurements of mass concentration polychlorinated dibenzo-p-dioxins and dibenzofurans in samples atmospheric air by chromato-mass spectrometry.
Method for measuring the mass fraction of heavy metals in soils and soils using X-ray fluorescence analyzers of the X‑MET type, METOREX (Finland).
Chemical analysis of a substance is a complex multi-stage process, it is carried out in a certain sequence, which is usually described in the analysis methodology specific object.
The analysis of any samples of a substance, including samples of the substance of environmental objects, is carried out in a certain sequence of its stages:
1. Sampling of a substance (in the field in ecology);
2. Obtaining a representative laboratory and analytical sample of the analyte;
3. Preparation of the sample of the analyte for the measurement of the analytical signal;
4. Creation of conditions for measurements and preparation of measuring instruments;
5. Preparation of the reference substance (standard);
6. Carrying out direct measurements of the analytical signal of standards and preparing a method for comparison with the standard when applying physical methods of analysis;
7. Carrying out direct measurements of the analytical signal of the analyzed sample of the substance;
8. Processing the results of direct measurements - identification of components and calculation of the content of the analyte in the sample of the analyte (indirect measurements);
9. Evaluation of the acceptability of the chemical analysis result by checking its precision (repeatability, reproducibility) and correctness;
10. Registration of the results of the chemical analysis of the sample of the substance of the object of analysis.
The ecologist is obliged to use the services analytical laboratories, accredited for the right to perform chemical analysis of environmental substances An accredited laboratory is a legally independent laboratory whose employees have repeatedly confirmed their technical competence. The methodology should be classified as a national (GOST) or industry (OST) standard or industry document (RD, PND F).
An example of requirements for organizational documents for the protection of atmospheric air in the laboratory of an enterprise for control negative impact on the environment. The laboratory must have the following documents:
Regulations on the laboratory, its passport;
Documents on accreditation (attestation);
Certificates of verification of measuring instruments by state metrological authorities
Passports for state standard samples of the composition and properties of controlled objects;
Results of internal and external quality control of performed measurements;
Sampling acts and logs of their registration;
Certified measurement methods;
Logs of the results of environmental impact monitoring.
The result of a quantitative chemical analysis of a sample of a substance, including an ecological object, is expressed through mass fraction w (A) or mass concentration of the determined component A, C m (A).
An ecologist, for example, when assessing the pollution of a substance of environmental objects, submits for chemical analysis to an analytical laboratory selected samples of solid, liquid, gaseous, or heterophase substances weighing up to 1 kg. He is interested in the complete chemical composition or the content of one or more components (in the form of atoms, isotopes, ions, molecules, or groups of molecules with the same properties) in the sample of the substance of the object of analysis - in soils, in plants, in bottom sediments, in natural waters , in atmospheric air and other ecological objects.
Mass fraction w (A) component A is the ratio of mass m (A) component BUT, substance present in the sample total mass substance samples, m (thing), which went to the analysis:
w (A) \u003d m (A) / m(item), w / r
Mass fraction of the component BUT in a sample of a substance can be converted into its percentage:
w (A) \u003d × 100,%
Volume fraction of the liquid component BUT in a sample of a liquid substance or gaseous component BUT in a sample of a gaseous substance is calculated as:
w (A) \u003d 100,%,
where V (A) - volume of liquid or gaseous component BUT in total V total samples of a liquid or gaseous substance;
In international practice, they use the way of expressing the mass fraction as one part of a component into a large number of other parts:
parts per hundred , %, pph, g∙100/kg;
parts per thousand , ‰, ppt, g/kg;
parts per million , ppm, mg/kg, g/t;
parts per billion , ppb, μg/kg, mg/t;
To quantify the content of the component BUT in liquid and gaseous matter, the concept component concentration BUT.
Component A concentration (C(A)) is a value that characterizes the relative content of a given component in a multicomponent substance and is defined as the ratio of the number of component particles BUT(molar concentration of the component BUT, molar concentration of component equivalent BUT) or the mass of the component BUT ( mass concentration of the component BUT), related to a certain volume of liquid or gaseous substance.
The concentration of a component is always a named value, it makes sense for the component BUT specific name. This is also reflected in the definition of concentration, which emphasizes that we are talking about the relative content of a given component in the volume of a multicomponent liquid or gaseous substance.
The basic unit of measure for the number of particles of a component (n) in the International System of Units physical quantities(SI system), adopted for use in the USSR in 1984, is 1 mol. 1 mol particles of any component that is of interest to us in the form of such structural chemical units as an atom (element), isotope, functional group, including an ion, or molecule, contains 6.022 × 10 23 such particles in any volume or mass of matter. thousandth part 1 mol(multiple unit) is denoted mmol ( read millimole).
Number of component particles BUT (n (A)) in any mass of the component BUT (m(A)) calculated by the formula:
n (A) \u003d m (A) / M (A), mol,
where m (A) - component mass A, g; M (A) - relative molar mass of the component A, g/mol;
In the international system of units of physical quantities, according to GOST 8.417-2002 “GSI. Units of quantities", the main names for the concentration of components in the volume of a liquid or gaseous substance are molar concentration of the component, mol / m 3, and mass concentration of the component, kg / m 3.
Molar concentration of component A in solution – C m (A) - is the particle number content of the component A n (A) per unit volume V
C m (A) \u003d n (A) / V; or C m (A) \u003d m (A) / [M (A) V . ]
The molar concentration of a component is measured in mol / m 3; mol / dm 3, mmol / dm 3 mol/l.)
An example of a recording form in documents: C m (NaCl) \u003d 0.1 mol / dm 3 \u003d 0.1 mmol / cm 3 (in analytical practice for internal use also use the following form of writing: 0.1 M NaCl).
Both in analytical practice and in various types of professional activities, including ecology, concentration expressed in mass units is used.
Mass concentration of component A is the mass content m (A) component BUT per unit volume V liquid or gaseous substance, is calculated as:
C m (A) \u003d m (A) / V. ,
The mass concentration of the component is measured in kg / m 3; submultiple units are also used - g / m 3, g / dm 3, mg / dm 3 etc. (for intralaboratory use, a unit is allowed g/l, g/ml).
An example of a recording form: C m (NaCl) \u003d 0.1 g / dm 3, (in analytical practice for internal use the notation form C m (NaCl) \u003d 0.1 g / l \u003d 0.1 mg / ml is allowed).
Knowing the mass concentration of the component BUT in solution, you can calculate its molar concentration and vice versa.
C m (A) \u003d C m (A) / M (A), if C m (A) expressed in g / dm 3,
C m (A) \u003d C m (A) M (A), if C m (A) expressed in mol / dm 3.
Methods for expressing the concentration of a component in a solution and the relationship between various types concentrations are given in Annex 3.
In ecology, the content of determined components in samples of a liquid substance is usually expressed through mass concentration in units g / dm 3, mg / dm 3, mcg / dm 3, in samples of a gaseous substance - in units g / m 3, mg / m 3 μg / m 3.
The mass of the sample m (thing) can be measured with the required accuracy on an analytical balance, the volume V can be measured with the required accuracy using measuring utensils. Weight of the component A, m (A), or the number of particles of the component A, n (A), it is impossible to directly measure the substances in the sample, they can only be measured indirectly (calculated using the appropriate formula, found from the calibration graph). To this end, various methods of quantitative chemical analysis.
R 50.2.008-2001
State support system
unity of measurements
TECHNIQUES FOR QUANTITATIVE
CHEMICAL ANALYSIS
GOSSTANDART OF RUSSIA
Moscow
Foreword
1 DEVELOPED by the State Unitary Enterprise All-Russian Research Institute of Metrology. DI. Mendeleev State Standard of Russia
INTRODUCED by the Department of Metrology of the State Standard of Russia
2 ADOPTED AND INTRODUCED BY Decree of the State Standard of Russia dated June 20, 2001 No. 244-st
3 INTRODUCED FOR THE FIRST TIME
R 50.2.008-2001
State system for ensuring the uniformity of measurements
QUANTITATIVE CHEMICAL ANALYSIS TECHNIQUES
Introduction date 2002-01-01
1 area of use
These recommendations are intended for state scientific metrological centers conducting metrological examination of documents for methods of quantitative chemical analysis (hereinafter referred to as metrological examination of the MKCA) in accordance with GOST R 8.563.
2 Normative references
GOST 8.221-76 State system for ensuring the uniformity of measurements. Moisture and hygrometry. Terms and Definitions
a) a document or a draft document regulating the ICCA;
b) terms of reference for the development of the ICA or another document containing the initial data for development (except when the relevant data are contained in state, interstate or international standards applicable to the analyzed object);
c) a copy of the certificate of metrological certification of the ICCA (if it was carried out). At the same time, the Applicant may submit additional materials: the program and results (in the form of reports, protocols) of the experimental or computational evaluation of the metrological characteristics of the MKCA, regulatory documents (including departmental ones) regulating the control of the accuracy of measurement results, etc. In addition, additional materials are submitted Applicant at the request of the SSMC conducting the examination (see).
If the Applicant considers it necessary to formulate questions for examination, then they must be set out in writing (for example, in cover letter to the GNMC).
5 Contents of the metrological examination of the ICAC
5.1 In the general case, during the metrological examination, the MKCA is subjected to critical analysis (evaluate):
The correctness of the names of the measured quantities and the designations of their units;
Choice of measuring instruments (including standard samples);
Compliance of the metrological characteristics of the MKCA with the specified requirements;
Procedures for monitoring the error of measurement results;
Completeness of statement of requirements, rules and operations;
Correctness of metrological terms.
5.2 At the request of the Applicant or in connection with the peculiarities of the appointment of the ICCA, other aspects can be considered during the metrological examination, for example: the metrological level of this technique in relation to other methods of a similar purpose, the prospects for standardization of the ICCA, the rationality of choosing the method of analysis.
6 The procedure for the metrological examination of the ICCA
6.1 The metrological examination of the MKCA is carried out by an expert or a group of experts authorized by the head (deputy head) of the SSMC.
An expert can be an employee of the SSMC who has worked in it for at least three years, has experience in attestation (development) of at least five IACs, and is familiar with domestic and international regulatory documents related to ensuring the uniformity of measurements. It is preferable that the expert (leader of the group of experts) has a basic higher education in the field of chemistry and is a certified expert of the Accreditation System for Analytical Laboratories (Centers). The expert must be aware general principles and methods for estimating measurement errors -, features of CCA as a measuring procedure, specific methods and techniques for ensuring the reliability of CCA results -, the role and place of CCA in monitoring product quality and the state of environmental objects -. The expert should systematically improve his qualifications, in particular, get acquainted with the relevant publications in specialized scientific and technical periodicals.
Experts are responsible for the correct, objective and timely performance of work, as well as for non-dissemination of confidential information. The head of the group of experts formulates tasks for the members of the group, summarizes their assessments and opinions.
6.2 The metrological examination of the MKCA includes the following stages:
Registration of documents submitted for examination;
Preliminary analysis of documents;
Request for additional documents (if necessary), their registration;
Assessing the compliance of the ICCA with metrological requirements;
Drawing up an expert opinion, its approval and transfer to the Applicant.
6.3 Documents received for metrological examination are registered in a journal, the recommended form of which is given in. It is allowed to combine the registration of documents at the ICCA with the registration of other types of documents subject to metrological examination, for example, draft standards.
7.2.5 When presenting the ICCA regulating the measurement of several quantities characterizing the chemical composition, their general name is sometimes used: “contenti ]. When examining such ICCA, it is necessary to make sure that the use of a generic name does not lead to a reduction or distortion of measurement information, does not create prerequisites for different interpretations of the ICCA text. A generalizing name should not be used when describing specific measurement tasks, when indicating metrological characteristics, as well as in explanations of calculation formulas and when reporting measurement results.
7.2.6 Units of measured values must comply with GOST 8.417, taking into account the governing document.
7.2.7 Examples of typical errors:
a) “The amount of zinc in 10 cm 3 of a solution is 15 mmol” instead of the correct “Amount of zinc substance in 10 cm 3 of a solution is 15 mmol”;
b) “Dissolved oxygen 60 µmol / dm 3” instead of the correct “Molar concentration of dissolved oxygen 60 µmol, dm 3”;
d) “Number of cadmium ions in the calibration solution 2.00 μg/5 cm 3 ” instead of the correct “Mass of cadmium in 5 cm 3 of the calibration solution 2.00 μg”;
e) "Dry residue in water 5 mg / 100 g" instead of the correct "Mass fraction of dry residue in water 0.05%".
7.3 Evaluation of the choice of measuring instruments
a) conformity of the purposes of application of the selected measuring instrument (including the standard sample) with the purpose fixed in the description of the type or in the technical documents for the measuring instruments;
b) the possibility of using a measuring instrument under specified conditions;
c) achievability of the required accuracy of measurement results when using a measuring instrument with the metrological characteristics established for this type;
d) the rationality of the choice of measuring instruments;
e) compliance with the requirements for measuring instruments used in the field of distribution of state metrological control and supervision.
7.3.2 Information about the purpose and main characteristics of measuring instruments of approved types can be borrowed from descriptions of types, from publications in the journals "Izmeritelnaya Tekhnika", "Legislative and Applied Metrology", as well as from databases formed by VNIIMS (for measuring instruments) and UNIIM (for state standard samples).
7.3.3 The achievability of the required accuracy is assessed by calculating the limits of the corresponding instrumental component of the error of the measurement results and comparing the found value with the limits (boundaries) of the error specified in the document for the MKCA. This procedure is sufficient in cases where the instrumental component of the error prevails over the methodological one.
Examples of detected errors:
a) To measure the height of the chromatographic peak, a ruler with a division value of 1 mm is used; tolerance limits ± 0.5 mm. The height of the peak of the determined component, corresponding to the lower limit of the mass concentration of the component in the analyzed object, is» 4 mm. The limits of the relative measurement error of the peak height in this case will be ± 12%, which clearly does not correspond to the assigned error characteristic of the measurement result of the mass concentration of the component ± 10%, specified in the document for the MKCA.
b) The method for measuring the mass concentration of a component in emissions from an industrial enterprise involves taking a gas sample using an aspirator (at a constant value of its volumetric flow rate of 4 dm 3 /min) into an absorption solution and subsequent analysis of the solution by the photocolorimetric method. The norm for the limits of the relative error in measuring the mass concentration of a component when monitoring sources of atmospheric pollution is ± 25%. The limits of the relative error in the analysis of the absorbing solution by the photocolorimetric method are usually 10% - 20%. To measure the volumetric flow rate of the gas flow, a rotameter with upper limit measurements of 20 dm 3 /min and the limits of the permissible basic reduced error ± 5%. The limits of the relative error of volumetric flow measurements (with the introduction of corrections) will be ± 25%. Comparison of the values of the components of the error with the norm indicates the impossibility of achieving the required accuracy when using the selected type of flowmeter.
7.3.4 When evaluating the rationality of the choice of measuring instruments, recommendations , , , as well as GOST R 1.11 can be used.
7.3.5 If the MKCA is intended for use in the field of distribution of state metrological control and supervision, then the expert must make sure that the types of measuring instruments used are registered in the State Register of Approved Types of Measuring Instruments, standard samples - in the State Register of Approved Types of Standard Samples.
7.3.6 It should be borne in mind that the sampling and dosing devices used in the IAC may have either the status of measuring instruments or the status of auxiliary equipment. In the latter case, evaluation is not carried out.
7.3.7 Along with substances and materials that have the status of measuring instruments (reference materials for the composition and properties of substances and materials according to , VNIIM reference materials according to , certified mixtures according to ), pure substances and reagents produced according to standards and specifications can perform the functions of measures in the ICCA. manufacturer's conditions (substances of known composition according to), as well as pure substances, solutions, mixtures obtained according to the procedure regulated in the document for the ICCA.
7.4 Evaluation of the conformity of the metrological characteristics of the MEXA to the specified requirements
a) terms of reference for the development of the ICCA or other documents, the requirements of which apply to this ICCA. (Such documents can be standards, specifications, guidelines, test programs, etc.);
b) GOST R 8.563 - in terms of indicating the measurement range and the form of presentation of the error characteristics.
The task of the expert is also to identify unreliable attributed characteristics of the measurement error or erroneous conclusions about the compliance of the measurement error with the established standards.
7.4.2 The measurement ranges (ranges of values of the measured quantity) indicated in the document for the MKCA and the assigned error characteristics are compared with the requirements given in the documents on, listing a).
Examples : The metrological characteristics of the MKHA of natural and waste waters are compared with the requirements of GOST 27384 and GOST 8.556, the metrological characteristics of the MKHA of atmospheric air are compared with the requirements of GOST 17.2.4.02.
7.4.3 If the requirements for error are not explicitly established, then the limits (limits) of the error specified in the document for the MKCA are compared with a tolerance for a controlled value.
Example . The technical specifications for the chemical product indicate that the mass fraction of the impurity component "B" (Win) should not exceed 0.50%. During the control, it is necessary to reliably distinguish a product of good quality fromWin= 0.50% and product withWin= 0.51%. To do this, it is necessary to obtain measurement results, the error of which does not exceed 0.003% (with appropriate economic justifications - 0.005%).
Useful guidelines for making such comparisons are provided in the recommendations , , ; for chemical analysis, the methodology is described in .
7.4.4 Sometimes the developers of the MKCA do not limit the measurement range from above, referring to the possibility of varying the mass of the sample taken for analysis, its dilution, etc. This practice does not meet the requirements of GOST R 8.563.
Other examples of inconsistencies:
Indication of "limit of detection" instead of the lower limit of the measurement range;
Representation of the characteristics of the measurement error in a form that does not allow specifying its value for each of the values of the measured quantity in the measurement range;
Indication of the characteristics of only the random component of the error;
Indication of the error control standard (without specifying the error characteristic).
7.4.5 If the expert doubts the reliability of the attributed characteristics of the measurement error or the correctness of the conclusions about the compliance of the measurement error with the established standards, then he must approximately calculate the error limits. Sources of doubt can be personal experience and intuition of an expert, significant differences in the characteristics of the error from those established for similar ICCA, a clearly simplified data processing algorithm, inconsistency in the characteristics and standards for error control, etc.
In most cases, it is advisable to carry out such a calculation for the smallest (largest) value of the measured quantity. The general calculation methodology is described in , , calculation algorithms are given in , -, in relation to chemical analysis - in the recommendations , . In addition, experts may refer to the EURAHIM document. The expanded uncertainty calculated in accordance with this document (at coverage factors of 2 and 3) is almost equal to the margin of error at a confidence level of 0.95 and 0.99.
When performing calculations, the expert should rely on the experimental data provided by the Applicant, information on the metrological characteristics of measuring instruments, standards for controlling error components (if they are given in the document for the ICCA).
a) the term "error" is used instead of "margin of error" or "margin of error";
b) the term “error characteristic” (or “accuracy indicator”) is used without specifying which characteristic is meant: “error margins”, “error limits” or “standard deviation of error”;
c) the term "margin of error" is used with an indication of a probability other than one;
d) the term "margin of error" is used without indicating the confidence level;
e) the limits of the relative error are indicated with an excessive number of significant figures (for example, ± 19.8% instead of ± 20%);
f) the limit of the measurement range is indicated with an excessive number of significant figures (for example, 100.0 mg/dm 3 instead of 100 mg/dm 3);
g) the limits of the relative error of measurements of the mass fraction of the main component in the technical product are indicated without taking into account the restrictions imposed by physical model(± 2.0% for upper limit of measuring range 99.5%);
i) the limits of the relative error of the measurement result of the volume fraction of the impurity component in the technical product are ± 100%;
j) the values of the characteristics of the random component of the error are indicated without explanation of the conditions to which they correspond (for example, conditions of convergence, intra- or inter-laboratory reproducibility);
k) the error characteristic is established only for the simplest model mixture (i.e. without taking into account real accompanying components) or for an unreasonably narrowed range of values of external influencing factors;
l) the error characteristic is established without taking into account the stages of sampling and sample preparation, although these stages are included in the ICA.
7.5 Evaluation of measurement uncertainty control procedures
7.5.1 The expert assesses:
Availability of operational control procedures in the ICCA;
The correct choice of means of control;
Interconnection of control standards and measurement error characteristics.
7.5.2 It should be borne in mind that the control procedure may cover all stages of the ICCA at once (“integrated control”) or only some of them. Methods for comprehensive control of measurement errors (analyses), as well as their convergence and reproducibility, are described in the recommendation. The control of individual stages is carried out in cases where complex control cannot technically be implemented or is irrational. Such control can also be carried out in addition to the complex one; in this case, the degree of separation or extraction of components, the error in constructing the calibration characteristic and its stability are most often controlled. In all cases when the value of the measured quantity (including intermediate) is calculated by averaging the results obtained during repeated measurements (determinations), it is advisable to control their convergence.
7.5.3 The document for the MKCA may not describe the error control procedures, but it must contain an indication of the control in accordance with any regulatory document.
Example . When analyzing drinking water error control can be carried out according to GOST R 51232; when analyzing gold - according to GOST 27973.0; when analyzing mineral raw materials - according to the industry standard; when analyzing natural water in the network laboratories of Roshydromet - according to the guidance document.
7.5.4 When assessing the correctness of the choice of control means, the expert must pay attention to the ratio of the boundary (limit) of the error of the measurement result according to the MKCA to the boundary (limit) of the error of the control. To ensure the reliability of control, this ratio, as a rule, should be at least 3 (if there is an appropriate justification, at least 2).
If a mixture (solution) is used as a means of control, the method of preparation of which is described in the appendix to the ICA, then the expert must approximately calculate the margins of error with which the content of the analyte in the mixture (solution) is established. In this case, recommendations can be applied.
If a standard sample is used as a means of control, then its category should correspond to the scope of the ICCA.
7.5.5 When evaluating the relationship between operational control standards and measurement error characteristics, it is advisable to be guided by the recommendation for integrated control, recommendations , - for control of the construction error and stability of the calibration characteristic. The expert should pay attention to the clarity of the formulation of the conditions for the control of intralaboratory reproducibility, since the control standard depends on which of the factors (time, operator, equipment, calibration) vary from analysis to analysis. This dependence also takes place when controlling the error by the method of additions; sample dilution method; a method that combines additive and dilution. If the analysis of the sample without additive and with the additive is carried out under conditions of constancy of the above factors, then the error control standard calculated by the method will be significantly overestimated.
7.5.6 Examples of typical errors:
a) the terms "control of the convergence of the results of determinations", "standard for the control of the convergence of the results of the determinations" are used without indicating which parameter is controlled: "the range of the results of the determinations", "deviation of the result of the determination from the arithmetic mean ...", the standard deviation of the results definitions”, “standard deviation of the arithmetic mean...”, etc.;
b) the allowable discrepancy between the two results of the analysis is given without specifying the conditions for obtaining them and the confidence level;
d) the standard for "the range of two results of parallel determinations, referred to the arithmetic mean ( R = 0.95)”, equal to 30%, does not agree with the limits of the relative error of the analysis result ± 10%, R= 0.95 (analysis includes two determinations).
7.6 Evaluation of the completeness of the statement of requirements, rules and operations
7.6.1 The examiner should review the sections of the ICCA document and its appendices in sequence. At the same time, it is advisable to ask the questions: “Is there enough information to carry out the analysis with the required accuracy?”, “Are there any provisions in this section that are not consistent with the requirements of GOST R 8.563, other state standards, or with other provisions of the document for the ICA?”, “Not does this wording allow various interpretations, which can cause an uncontrolled error?
7.6.2 The expert should pay special attention to those requirements (rules, operations) that most affect the quality of the data received. In this case, it is necessary to be guided by the information available in the literature on the limitations and sources of error characteristic of the methods of sampling and analysis being implemented, as well as the estimates obtained when calculating the error limits of the measurement results (see ).
7.6.3 The shortcomings most often found in the documents for the ICCA:
Limitations due to interfering sample components are not specified;
The requirements for the content of the main component in the pure substance used for the preparation of calibration mixtures have not been formulated;
The shelf life of calibration mixtures has not been established;
There are no calibration quality criteria;
The criteria for identification of components, separation criteria (when analyzing multicomponent samples by chromatography, mass spectrometry, spectrophotometry, etc.) are not given;
The term "parallel definitions" is used without specifying exactly which operations must be repeated and which remain common;
The designations of the various measured quantities coincide;
The designations of the quantities included in the formula for calculating the result of the analysis are not deciphered;
There are no requirements for formatting the analysis result.
7.6.4 It is not the task of the expert to eliminate grammatical errors and stylistic inaccuracies present in the document at the ICCA.
7.7 Validation of metrological terms
7.7.1 Metrological terms must comply with GOST R 1.12 and.
7.7.2 In ICCA documents, the terms “analyzed”, “determined”, “measurable”, “controlled” are often used as synonyms, which creates uncertainty in interpretations. When drawing up conclusions, it is advisable for experts to use the following set phrases:
Analyzed sample, analyzed substance (material), object of analysis;
The component being defined;
Measured value;
Controlled parameter, control standard.
7.7.3 In the regulation of the ICCA, which provide for the repeated execution of a sequence of operations, it becomes necessary to use two terms, one of which applies to a single sequence of operations, the other - to the totality of such sequences. In such cases, combinations of terms are used: “observation and measurement”, “single measurement” and “two (three) multiple measurements”, “single measurement” and “multiple measurement” (if the number of measurements is four or more), “single determination” (or "definition") and "analysis". It is necessary to pay attention to the fact that only one of the specified (or similar in meaning) combinations of terms is used in the ICCA document.
7.7.4 The examiner should take into account that chemical analysis often acts as a step in the testing or control procedure, and therefore the relevant terms may be used in the ICCA document. In particular, the measured value can be interpreted as an indicator of product quality, and the result of measurements (analysis) - as a test result or indicator value.
The form of the register of documents received for metrological examination
|
Applicant |
Date of receipt of documents |
List of received documents |
Date of request for additional documents |
Date of receipt of additional documents |
List of additional documents received |
Experts |
Date of approval of the expert opinion |
Additional documents request formHead ________________________________ applicant enterprise REQUEST Based on the results of the preliminary metrological examination _________ number (index) and name of the document (draft document) in which the ICAC is regulated I propose to send to __________________________________ before ________________ name GNMC the following additional documents: _______________________________________ ________________________________________________________________________ The examination is carried out in accordance with _______________________________________ number and date of the letter (contract) Contact phone _____________________ Deputy Director of the SSMC __________________ ____________________________ signature full name |
Form of expert opinion 1)_________________________________________________________________________ __________________________________ organization conducting the review APPROVE ____________________________________ position ___________ _____________________ signaturedecryption signature ___________________ the date CONCLUSION according to the results of metrological examination of the method of quantitative chemical analysis 1), regulated in _____________________________________________________, number (index) and name of the document (draft document), ________________________________________________________________________ organization-developer, its address certified 2) _________________________________________________________ organization that certified the methodology, certificate number The examination was carried out on the basis of __________________________________________ number of the letter (contract), _________________________________________________________________________ organization that submitted the ICCA for examination Additional materials provided by the expert: ________________________ technical task, _________________________________________________________________________ certificate of attestation, reports, protocols, etc. Methodology (not) designed for use in the areas of distribution of state metrological control and supervision. Conclusions on the compliance of the MKCA with the requirements of GOST R 8.563-96 “State system for ensuring the uniformity of measurements. Measurement methods": a) Names of measured quantities and designations of their units ( with the exception of those indicated in remarks no. ________) meet the requirements of GOST 8.417-81 “State system for ensuring the uniformity of measurements. Units of physical quantities”, ________________________________________________________________ _________________________________________________________________________ other documents b) Choice of measuring instruments ( with the exception of those indicated in remarks No. _______ _) satisfies the conditions of the measurement problem and can be recognized as rational. Types of selected measuring instruments, including standard samples( _____), approved by the State Standard of Russia 3) . c) Measuring range 4) ( not) meets the requirements of __________________________ technical task, ______________________________________________ (see also note no. ___) 5) . specifications, standard, etc. d) Measurement error characteristics ( not) comply _________ ____________________________________________ (see also note no. _____) 6) . terms of reference, specifications, standard, etc. e) Measurement accuracy control procedures ( not) are provided; control standards are linked ( not linked) with measurement error characteristics ( see also note no. _____). e) Requirements, rules and operations ( with the exception of those indicated in remarks no. _____) are presented with sufficient completeness to obtain measurement results, the error of which does not exceed the established limits 7). g) Metrological terms ( with the exception of those indicated in remarks no. _____) correspond to GOST R 1.12-99 “State standardization system of the Russian Federation. Standardization and related activities. Terms and Definitions” and “State System for Ensuring the Uniformity of Measurements. Metrology. Basic terms and definitions”. and) ______________________________________________________________________ other expert assessments Remarks Expert ( s): ________________________________________________________________________ positionsignaturesignature transcript __________ 1 ) Option "Measurement methods". 3) They are given only for the MKCA, intended for use in the areas of distribution of state metrological control and supervision. 4) Variant: "range of measured values". 5) Option: "measurement range not set". 6) Option: "characteristics of the measurement error have not been established." 7) Option: "... established limits." |
Examples of block diagrams of the MKHA
OP- alloy sampling; measure the masses t 1 and t 2, G.
P- sample preparation: dissolution by heating, cooling, dilution.
And- potentiometric titration of silver with sodium chloride solution,V 1 and V 2 - volumes of solution used for titration, cm 3 .
BP-calculation of the results of determinations; T Na C l / Ag - titer of sodium chloride solution for silver, g/cm 3 ; X 1 and X 2- mass fraction of silver in samples, %.
Control of the convergence of the results of determinations and calculation of the average value of the mass fraction of silver in the alloyXcR(result of analysis).
Alloy test.
titratable solution.
Figure D.1 - Block diagram of the technique for measuring the mass fraction of silver in alloys
OP- gas sampling; during sampling, sample parameters are measured: temperature T, ° WITH; Atmosphere pressure r a, kPa; underpressureDR, kPa; selection timet , min; volume flowQ, dm 3 /min.
PP- extraction of methanol from a gas sample using a sorption tube.
E- extraction of methanol and measurement of the volume of the extractVuh, cm 3 .
And-introduction of three aliquots of the extract into the evaporator of the chromatograph and obtaining analytical signalsS 1 , S 2 , S 3 .
Monitoring the convergence of analytical signals and calculating the average valueS.
PV- preliminary calculation; Cm- mass concentration of methanol in the extract, mg/cm 3 .
BP- calculation of the measurement result; Hm- mass concentration of methanol in a gas sample at a temperature of 273 K and a pressure of 101.3 kPa, mg/m 3 .
PGR-1 - preparation of calibration solution 1 with mass concentration of methanol, mg/cm 3 .
Lines (2), (3), (4) correspond to calibration solutions 2, 3, 4.
Calculation of calibration coefficients for solutions 1-4, control of convergence of coefficients and calculation of the average TO.
Gas sample/
Sorbent with methanol.
Extract and calibration solution
Figure D.2 - Structural diagram of the technique for measuring the mass concentration of methanol in gas emissions by the chromatographic method
Rabinovich S.G. Measurement errors. - L .: Energy, 1978
Semenko N.G., Panova V.I., Lakhov V.M. Standard samples in the system for ensuring the uniformity of measurements. - M.: Publishing house of standards, 1990
Kateman G., Piipers F.V. Quality control of chemical analysis. - Chelyabinsk: Metallurgy, 1989
Dörfel K. Statistics in analytical chemistry. - M.: Mir, 1994
Buytash P., Kuzmin N.M., Leistner L. Quality assurance of chemical analysis results. - M.: Nauka, 1993 RD 50-160-79 Implementation and application of GOST 8.417-81 “State system for ensuring the uniformity of measurements. Units"
OST 52.04.11-82 Atmospheric ozone. Terms, letter designations and definitions of basic quantities
RD 50-674-88 Guidelines. Metrological support for quantitative chemical analysis. Key points
[ 22 ] MI 2377-98 Recommendation. State system for ensuring the uniformity of measurements. Development and certification of measurement methods
[ 27 ] MI 2083-90 Recommendation. State system for ensuring the uniformity of measurements. Measurements are indirect. Determination of measurement results and estimation of their errors
MI 2232-2000 State system for ensuring the uniformity of measurements. Ensuring the efficiency of measurements in process control. Error Estimation with Limited Initial Information
Quantifying uncertainty in analytical measurements. Document Translation EURACHEM. - St. Petersburg: Christmas, 1997
[ 33 ] MI 2552-99 Recommendation. State system for ensuring the uniformity of measurements. Application of the "Guidelines for the expression of measurement uncertainty"
[ 34 ] MI 2335-95 Recommendation. State system for ensuring the uniformity of measurements. Internal quality control of the results of quantitative chemical analysis
[ 37 ] MI 1992-98 Recommendation. State system for ensuring the uniformity of measurements. Metrological certification of standard samples of the composition of substances and materials according to the preparation procedure. Key points
Keywords: method of quantitative chemical analysis, metrological examination, state scientific metrological center, analyzed object, determined component, measured quantity, measuring instrument, characteristic of measurement result error
State system for ensuring the uniformity of measurements
QUANTITATIVE CHEMICAL ANALYSIS TECHNIQUES
General requirements for development, certification and application
State system for ensuring the uniformity of measurements. Quantitative chemical analysis procedures. General requirements for development, certification and application
OKS 17.020
Introduction date 2015-01-01
Foreword
1 DEVELOPED by the Federal State Unitary Enterprise "Ural Research Institute of Metrology" (FGUP "UNIIM")
2 INTRODUCED technical committee on standardization TC 53 "Basic norms and rules for ensuring the uniformity of measurements"
3 APPROVED AND PUT INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology dated November 22, 2013 N 1940-st
4 INTRODUCED FOR THE FIRST TIME
The rules for the application of these recommendations are established in GOST R 1.0-2012 (section 8). Information about changes to these recommendations is published in the annual (as of January 1 of the current year) information index "National Standards", and the official text of changes and amendments - in the monthly information index "National Standards". In case of revision (replacement) or cancellation of these recommendations, a corresponding notice will be published in the next issue of the monthly information index "National Standards". Relevant information, notification and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (gost.ru)
Introduction
Introduction
Methods of quantitative chemical analysis (hereinafter referred to as MKCA), which are one of the varieties of measurement methods and are used in the analytical control of the composition or properties of substances, materials, environmental objects, objects of technical regulation, biological and other objects, as well as in the transfer of the size of units from standards and for the certification of standard samples, constitute a significant part of the measurement methods used both in the field of state regulation of ensuring the uniformity of measurements, and outside it. At the same time, regardless of the scope of application, MCCA have common specifics associated with the presence and implementation of special procedures inherent in quantitative chemical analysis, such as the availability of various procedures for sampling and stabilizing samples for different objects, the presence of special conditions for storage and transportation of samples of chemically aggressive objects. , the presence of specific procedures for opening samples (chemical, thermal decomposition, etc.), the availability of special procedures for preparing samples for analysis related to the transfer of the analyte (component) to a state convenient for analysis (measurement) (various methods of extraction, concentration) and etc. Each of the above procedures can cause its own, sometimes quite significant contribution to the overall error (uncertainty) of the analysis results, causing their unreliability, if any of the listed factors has not been sufficiently well analyzed, evaluated and taken into account in the process of developing the ICA and in assessing its suitability for the intended purpose - MKCA validation (suitability assessment according to GOST ISO/IEC 17025-2009). Depending on the scope of the MCCA, the final stage of its development may be the methodology validation procedure in accordance with GOST ISO / IEC 17025-2009 (for MCCA intended for use outside the scope of state regulation of ensuring the uniformity of measurements) or the certification procedure (according to Federal Law N 102-FZ " On Ensuring the Uniformity of Measurements" and GOST R 8.563-2009) for the MKCA used in the field of state regulation of ensuring the uniformity of measurements), which can be carried out on the basis of the results of the MKCA validation. At the same time, the MKCA is validated by the developer or user of the methodology, and the MKCA is certified by those accredited for this type of activity in the field of ensuring the uniformity of measurements. legal entities(individual entrepreneurs).
The reliability and traceability of the analysis results obtained using a particular ICCA depends on its metrological level, which, in turn, is determined by the quality of the implementation of the ICCA development procedure itself and its final stages - validation, certification.
The purpose of these recommendations is to describe the system of provisions and recommendations that should be taken into account when carrying out the procedures for the development of the MCCA, taking into account the above specifics of quantitative chemical analysis and the need to apply various procedures for assessing its compliance with the intended purpose, as the final stage in the development of the MCCA (depending on the scope of its application), as well as the features and procedure for the application of the MCCA, including the MCCA, developed on the basis of international standards governing standardized methods of measurement (analysis).
These recommendations are developed in development of the provisions of GOST R 8.563-2009.
1 area of use
1.1 These recommendations define a system of provisions and recommendations that should be considered in the development, validation, certification and application of quantitative chemical analysis methods, which are one of the varieties of measurement methods.
_______________
According to GOST ISO / IEC 17025 - suitability assessment.
1.2 These recommendations apply to methods of quantitative chemical analysis (hereinafter referred to as MKCA), as well as to test methods, test methods, measurements, analysis, if they are or contain MKCA.
2 Normative references
In these recommendations, normative references to the following normative documents are used:
GOST 8.315-97 State system for ensuring the uniformity of measurements. Standard samples of the composition and properties of substances and materials. Key points
GOST 8.417-2002 State system for ensuring the uniformity of measurements. Units
GOST 17.4.3.03-85 Nature protection. Soils. General requirements for methods for the determination of pollutants
GOST 17.2.4.02-81 Nature protection. Atmosphere. General requirements for methods for the determination of pollutants
GOST 27384-2002 Water. Standards of measurement error of indicators of composition and properties
GOST 28473-90. Cast iron, steel, ferroalloys, chromium, manganese metal. General requirements for methods of analysis
GOST ISO 9000-2011 Quality management systems. Fundamentals and vocabulary
GOST ISO/IEC 17025-2009 General requirements for the competence of testing and calibration laboratories
GOST R 8.563-2009 State system for ensuring the uniformity of measurements. Techniques (methods) of measurements
GOST R 8.568-97 State system for ensuring the uniformity of measurements. Test equipment certification. Key points
GOST R 8.596-2002 State system for ensuring the uniformity of measurements. Metrological support of measuring systems. Key points
GOST R 8.654-2009 State system for ensuring the uniformity of measurements. Requirements to software measuring instruments. Key points
GOST R 8.736-2011 State system for ensuring the uniformity of measurements. Multiple direct measurements. Methods for processing measurement results. Key points
GOST R 52361-2005 Analytical control of the object. Terms and Definitions
GOST R 52599-2006 Precious metals and their alloys. General requirements for methods of analysis
GOST R 54569-2011 Cast iron, steel, ferroalloys, chromium and manganese metal. Accuracy standards for quantitative chemical analysis
GOST R ISO 5725-1-2002 Accuracy (correctness and precision) of measurement methods and results. Part 1. Basic provisions and definitions
GOST R ISO 5725-2-2002 Accuracy (correctness and precision) of measurement methods and results. Part 2: Basic method for determining the repeatability and reproducibility of a standard measurement method
GOST R ISO 5725-3-2002 Accuracy (correctness and precision) of measurement methods and results. Part 3. Intermediate precision values of the standard measurement method
GOST R ISO 5725-4-2002 Accuracy (correctness and precision) of measurement methods and results. Part 4: Basic methods for determining the validity of a standard measurement method
GOST R ISO 5725-6-2002 Accuracy (correctness and precision) of measurement methods and results. Part 6. Using precision values in practice
RMG 54-2002 State system for ensuring the uniformity of measurements. Characteristics of calibration instruments for measuring the composition and properties of substances and materials. Method for performing measurements using standard samples
RMG 60-2003 State system for ensuring the uniformity of measurements. Blends certified. General development requirements
RMG 61-2010 State system for ensuring the uniformity of measurements. Indicators of accuracy, correctness, precision of methods of quantitative chemical analysis. Assessment Methods
RMG 62-2003 State system for ensuring the uniformity of measurements. Ensuring the efficiency of measurements in process control. Estimation of measurement error with limited initial information
RMG 63-2003 State system for ensuring the uniformity of measurements. Ensuring the efficiency of measurements in process control. Metrological examination of technical documentation
RMG 64-2003 State system for ensuring the uniformity of measurements. Ensuring the efficiency of measurements in process control. Methods and ways to improve the accuracy of measurements
RMG 76-2004 State system for ensuring the uniformity of measurements. Internal quality control of the results of quantitative chemical analysis.
PMG 44-2001 Rules for interstate standardization. Procedure for recognition of measurement methods
PMG 96-2009 State system for ensuring the uniformity of measurements. Results and characteristics of measurement quality. Presentation Forms
R 50.2.008-2001 State system for ensuring the uniformity of measurements. Methods of quantitative chemical analysis. Content and procedure for metrological examination
R 50.2.028-2003 State system for ensuring the uniformity of measurements. Algorithms for constructing calibration characteristics of measuring instruments for the composition of substances and materials and estimating their errors (uncertainties). Estimating the error (uncertainty) of linear calibration characteristics using the least squares method
R 50.2.060-2008 State system for ensuring the uniformity of measurements. Implementation of standardized methods for quantitative chemical analysis in the laboratory. Confirmation of compliance with established requirements
Note - When using these recommendations, it is advisable to check the validity of reference documents and classifiers in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or according to the annual information index "National Standards", which was published as of January 1 of the current of the year, and according to the issues of the monthly information index "National Standards" for the current year. If an undated referenced document has been replaced, it is recommended that the current version of that document be used, taking into account any changes made to that version. If the referenced document is replaced by a dated reference, it is recommended to use the version of this document with the year of approval (acceptance) indicated above. If, after the approval of these recommendations in reference document, to which a dated reference is given, a change has been made that affects the provision to which the reference is given, then this provision is recommended to be applied without taking into account this change. If the reference document is canceled without replacement, then the provision in which the link to it is given is recommended to be applied in the part that does not affect this link.
3 Terms and definitions
These recommendations use the terms according to GOST R 8.563, GOST R 52361, GOST ISO 9000, GOST R ISO 5725-1, PMG 96, RMG 61, as well as the following terms with the corresponding definitions:
3.1 quantitative chemical analysis; CCA: Experimental quantitative determination in the object of analysis (substance, material) of the content (mass concentration, mass fraction, volume fraction, etc.) of one or more components by chemical, physicochemical, physical methods.
Note - The result of the CCA is the established content of a substance component in a sample, expressed in units of physical quantities approved for use in the country, indicating the characteristics of its error (uncertainty) or their statistical estimates. The QCA result is a kind of measurement result.
3.2 method of quantitative chemical analysis; MKCA: A set of specifically described operations, the performance of which provides the results of a quantitative chemical analysis with established accuracy indicators.
Notes
1 Quantitative chemical analysis technique is a type of measurement technique.
2. The content of one or more components of the object of analysis is taken as a measured characteristic.
Note - As an indicator of the accuracy of the measurement technique, the characteristics of the measurement error in accordance with , uncertainty indicators in accordance with *, accuracy indicators in accordance with GOST R ISO 5725-1 can be used.
________________
* See section Bibliography, here and below. - Database manufacturer's note.
3.4 MKHA accuracy indicator: An indicator of measurement accuracy established for any CCA result obtained in compliance with the requirements and rules of this ICA.
Note - The values of the accuracy indicator can be assigned to any CCA result obtained in compliance with the requirements and rules specified in the ICCA document.
3.5 measurement accuracy rate: Values of an indicator of accuracy allowed for certain measurement purposes.
3.6 ICCA validation: A documented procedure for confirming the suitability of the ICCA for the achievement of its objectives, including the study and provision of objective evidence that the specific requirements for the specific intended use of the methodology are met.
3.7 metrological requirements for MKHA: Requirements for the characteristics (parameters) of the measurement procedure provided for by the ICCA, which affect the result and accuracy indicators, and the conditions under which these characteristics (parameters) must be provided.
3.8 influencing sample factors: Interfering components and other properties (factors) of the sample that affect the result and the value of the measurement accuracy indicator.
3.9 influencing factors of the technique: Factors, the values of which determine the conditions for carrying out measurements according to the MKCA, influencing the result and the value of the measurement accuracy indicator.
4 General provisions
4.1 MKCA are developed and applied in order to ensure the measurement of indicators of the composition and properties of substances, materials, objects of technical regulation, biological and other objects subject to analytical control, in accordance with the established metrological requirements for measurements, including requirements for measurement accuracy.
4.2 Metrological requirements for measurements performed during analytical control are established taking into account the specifics of the controlled objects and the purposes of using the measurement results.
4.3 The metrological requirements for measurements performed during analytical control include the requirements for:
- the type and characteristics of the measured quantity (indicator);
- unit of measured quantity (indicator);
- measurement range of the value (indicator);
- measurement accuracy;
- ensuring the traceability of measurement results;
- to the conditions of measurements;
- to the number of digits as a result of measurements (rounding of measurement results) - if necessary.
4.4 For the MKCA, related to the sphere of state regulation of ensuring the uniformity of measurements, in accordance with the federal executive authorities determine the mandatory metrological requirements for measurements, including indicators of measurement accuracy.
MKCA, designed, according to, to confirm the compliance of objects of technical regulation with the requirements of technical regulations, must also provide mandatory requirements in terms of compliance with:
- measured values (indicators) of the controlled object of technical regulation to the list of safety indicators established in it;
- units of measurement according to the ICCA units of quantities determined by the technical regulations;
- range of measurements according to the MKCA to the established (permissible) levels of safety indicators of objects of technical regulation;
- values of the accuracy indicators of the MKCA to the standards of measurement accuracy determined by the technical regulations (if any).
During the development of the MKCA, additional metrological requirements may be determined by the customer (developer).
4.5 For MKCA, not related to the scope of state regulation of ensuring the uniformity of measurements, the metrological requirements for measurements are determined by the customer (developer) of the methodology.
4.6 The development of the MKCA is carried out on the basis of plans, programs of national (industry) standardization, plans for the modernization of the organization's production, etc., depending on its purpose and scope.
4.7 The final stage in the development of the ICA used in the field of state regulation of ensuring the uniformity of measurements is its certification. The final stage in the development of the ICCA, which is not intended for use in the field of state regulation of ensuring the uniformity of measurements, is its validation or certification, performed on a voluntary basis.
4.8 The document for the ICCA is developed in accordance with the requirements of GOST R 8.563, these recommendations and the procedure established for the corresponding rank of the document in the field of standardization, which assumes the approval of a particular ICCA.
4.9 Certification of the MKCA is carried out in accordance with the procedure determined by GOST R 8.563 and these recommendations. Certification of MKCA related to the sphere of state regulation of ensuring the uniformity of measurements is carried out by legal entities and individual entrepreneurs accredited in accordance with the established procedure for certification of measurement methods in accordance with the approved scope of their accreditation.
4.10 Validation of the MCCA is carried out by its developer or, on his behalf, by a third-party organization competent in the field of CCA metrological support in accordance with these recommendations.
4.11 The use of the MCCA in a specific laboratory that is not the developer of the MCCA must be preceded by a procedure for its verification (implementation), confirming its feasibility in the conditions of this laboratory with the established accuracy indicators.
4.12 MKHA are used in strict accordance with their purpose and scope, which are regulated in the approved document for MKHA.
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