GOST 25086-87

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  ГОСТ 25086-87

GOST 25086−87 non-ferrous metals and their alloys. General requirements for methods of analysis (Change No. 1)

GOST 25086−87
Group B59

INTERSTATE STANDARD

NON-FERROUS METALS AND THEIR ALLOYS

General requirements for methods of analysis

Nonferrous metals and their alloys.
General requirements for methods of analysis

AXTU 1709

Date of introduction 1988−07−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 24.11.87 N 4241

3. REPLACE GOST 25086−81

4. The standard fully complies ST SEV 4645−84

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. The expiration time limit is removed by the Resolution of Gosstandart from 21.09.92 N 1225

7. EDITION with Change No. 1, approved in September 1992 (IUS 12−92)

1. This standard establishes General requirements for methods of analysis of non-ferrous metals and their alloys.

This standard does not apply to hard alloys and metals and alloys of high purity.

2. Sampling and sample preparation of metals and alloys are carried out according to GOST 24231 or according to normative-technical documentation for specific products.

(Changed edition, Rev. N 1).

3. For the analysis used a measuring laboratory glassware not lower than 2nd accuracy class according to GOST 29251, GOST 29227 (burettes, pipettes) and GOST 1770 (cylinders, beakers, flasks and test tubes), utensils and equipment according to GOST 25336, crockery and equipment (crucibles, boats, inserts for desiccators, etc.) according to GOST 9147, dishes made of transparent quartz glass (crucibles, flasks, test tubes etc.) according to GOST 19908, as well as crucibles and cups made of platinum according to GOST 6563, the dishes of glassy carbon brand SU-2000.

4. Used standardized measuring instrument must pass state verification. Used non-standardized analytical instruments and analytical systems are versatile needs to pass certification and verification by the RD 50−674, MI 1788 and GOST 8.326*.
______________
* In the Russian Federation there are PR 50.2.009−94.

Allowed the application along with the means of measurement specified in specific standard for method of analysis, other means of measuring this type providing metrological characteristics of the analysis standardized methods of analysis.

(Changed edition, Rev. N 1).

5. The used reagents must have a qualification not lower than «clean for analysis.» Allowed the use of the reagents lower qualifications when providing the metrological characteristics of the results analysis, standardized methods of analysis. Mandatory application reagents a higher qualification stipulated in the framework of analysis.

6. For the preparation of solutions and the analysis used distilled water according to GOST 6709, if no other.

7. In the expression «diluted 1:1, 1:2, etc.» and the designation (1:1), (1:2) and etc. the first digits stand for the volumetric part of the dilute reagent (for example, concentrated acid), the second volumetric portion the used solvent (e.g., water, butanol, etc.).

8. Substance content in solutions Express:

the relative density (), specifying the substance, which is density;

mass concentration, g/DMor g/cm;

molar concentration, mol/DM.

Substance content in metals and alloys to Express a mass fraction, %.

(Changed edition, Rev. N 1).

9. If the method of analysis not specified the concentration or the degree of dilution solution of reagent (acid, alkali, etc.), refers to a concentrated solution of the reagent.

10. Mass concentration of solution titrant establish not less than aliquotes three parts of the solution or three batches of material with known the contents of the designated component. The concentration define the component in its finding titration establish not less than three aliquote parts of the solution.

The accuracy of reducing the mass concentration determined by the specific conditions of preparation and the purpose of the solution.

11. For the preparation of solutions with known concentrations of metals used metals and their compounds, containing at least 99.9% of the main substance.

12. Weighing the analyte, the substance for making solutions with a known concentration of metals and sediment in gravimetric analysis is carried out, unless specifically authorized in the method of analysis, on the scales with the measurement error not more than 0,0002 g.

10−12. (Changed edition, Rev. N 1).

13. Preparation of solutions and analysis after each addition of the reagent the solution was stirred.

14. The designation of «hot» water (solution) means that the water (solution) has temperature greater than 70 °C, in other cases, the temperature of the water (solution) must be specified in the methodology analysis.

15. The analysis result should be the arithmetic mean of the results parallel definitions. The number of parallel measurements, average when calculating the result of the analysis specified in the analysis methods.

Numeric the value of the result of the analysis must end with the digit the same category as the value of the permissible discrepancies in the results parallel definitions specified in the method of analysis.

16. If in parallel with the analysis in the same conditions is carried out the control expertise to make the appropriate amendments in the results analysis, the number of parallel measurements in the control experience should to match the number of parallel measurements specified in the methodology analysis.

The amendment the results of the determination on the results of a control experiment is conducted by subtracting the values of the reference experiment from the result of the determination when the analysis of the sample.

17. The discrepancy between the largest and smallest results of the parallel definitions in the analysis sample or in a control experiment at a confidence probability =0.95 does not exceed the allowable divergence ( — convergence), the value of which is given in the method of analysis.

Allowed to submit for certain mass fraction, and calculate the values for the intermediate mass fraction by linear interpolation.

It is allowed to insert in the form of equations or tables that includes the whole mass fraction interval detectable component to be mounted in the method of analysis and divided into the subintervals within which the appropriate values can be taken constant.

If the discrepancy between the highest and lowest results of parallel measurements exceeds the value , normalized in the method of analysis, the analysis is repeated.

If in this case the discrepancy between the highest and lowest results of parallel measurements exceeds the normalized value , then performing the analysis according to this method cease to identify and address the causes of the observed rashiden

E.

18. The discrepancy between the results of the analysis of the same samples obtained in two laboratories, and in the same laboratory but under different conditions, with confidence =0.95 does not exceed the permitted variance () two results of the analysis (the reproducibility) is established experimentally and is shown in the method of analysis.

19. The accuracy of the analysis are controlled by state standard samples of composition (gsas). In the absence of a gas control analysis accuracy may be performed according to the industry standard sample (CCA) or standard samples of the enterprise (SOP) approved by GOST 8.315.

Allowed to control the accuracy of the analysis, additives analysis synthetic mixtures and by comparing the result of analysis with result analysis of the same samples obtained by other, less accurate standardized or certified methods of analysis.

20. Control precision analysis for standard samples is carried out by the assaying of the sample, the chemical composition of which corresponds to the requirements of the standard or other normative and technical documentation on composition of controlled material samples according to the method of analysis.

Mass the proportion of the designated component in the standard sample find among parallel definitions, regulated by the method of analysis.

Secondary arithmetic mean value of results of parallel measurements take played for the mass fraction of the designated component in the standard sample.

The discrepancy the highest and lowest results of parallel measurements with the analysis of the standard sample shall not exceed the values given in the method of analysis.

Analysis samples believed to be accurate, if the result of the analysis of a standard sample on the content of this component deviates from the certified characteristics not more than the value of 0.71 is given in the method of analysis.

If the difference between found and certified values mass fraction is not performed, the analyses by this method cease to ascertain the causes of the observed bias.

For the final result of the analysis take a satisfying result the requirements of section 17, subject to the satisfaction of the requirements of section 20.

21. The control accuracy of the analysis by the method of additions is performed by finding the mass fraction of the analyte in the test material after add the corresponding sample of the pure metal or aliquote part the standard solution is detectable component to the sample before carrying out analysis.

A lot additive (amount of a standard solution) is selected so that the analytical signal of the designated component increased by 2−3 times comparison with the analytical signal in the absence of additives.

For the sample with the additive must follow the terms of the analysis provided by the method of analysis.

In if the mass fraction of detectable component in the sample with additive exceeds the upper limit of the interval mass fraction, regulated by the method of analysis, it is necessary to lead to mass shares, corresponding to this interval.

This is achieved by the appropriate dilution of the solution of the analyzed sample or sample variation of the sample.

Definition the mass fraction of the component in the sample with the additive is carried out from the same number parallel definitions that in the analysis of the samples. The arithmetic mean the value of results of parallel measurements taken for the mass the share of this component in the sample with the additive. Found size Supplement find the difference between the found mass proportions of this component in the sample with the additive and the sample without additive.

The discrepancy the highest and lowest results of parallel measurements component in the sample with the additive should not exceed the value normalized in the method of analysis.

Analysis of samples believed to be accurate, if the found value differs from the additive introduced its value of not more than 0.71, where and  — the permissible discrepancy of the two results of the analysis for the sample and the sample with the additive, respectively.

For the final result of the analysis of samples take result satisfying the requirements of section 17, provided you meet the requirements p. 21.

22. The control accuracy of the analysis of samples for synthetic compounds is carried out by play is introduced into this mixture the mass fraction determined component by the method of analysis.

Definition the mass fraction of component in the synthetic mix is carried out simultaneously with the analysis of the samples from the same number of parallel definitions prescribed the method of analysis.

The discrepancy the highest and lowest results of parallel measurements this component in the analysis of the synthetic mixture should not exceed the value normalized in the method of analysis.

Analysis samples believed to be accurate, if you played mass fraction of the component in the synthetic mix is different from the one entered in the mix it the mass fraction of not more than the value of 0.71 is given in the method of analysis.

If the above difference between the reproduced and entered mass shares of the component is not satisfied the tests for this the method is stopped until the reasons that caused the observed bias.

For the final result of the analysis take a satisfying result the requirements of section 17, subject to the satisfaction of the requirements of section 22.

23. The control accuracy of the analysis of samples carried out by comparing them with the results of the analysis of the same samples obtained by a different method, included in the standard for the method of analysis or certified according to GOST 8.010* and having error not exceeding the error of the controlled methods.
________________
* In the Russian Federation GOST R 8.563−96.

Analysis of the samples is believed to be accurate when performing a difference of 0.71, where and  — the permissible discrepancy of the two results of the analysis, the numerical values of which is regulated in a specific controlled and control the methods of analysis.

For the final result of the analysis take a satisfying result the requirements of section 17 subject to the satisfaction of the requirements of section 23.

24. The calibration graphs are built in rectangular coordinates. Axis x lay a mass or mass fraction, or concentration in percentage of the designated component or function from it, and on the y-axis the value of the analytical signal, the measured parameter or function from him.

It is possible to use a calibration function that represents the equation of calibration curve.

17−24. (Changed edition, Rev. N 1).

The APP (Deleted, Rev. N 1).