GOST 22306-77
INTERSTATE STANDARD
METALS OF HIGH AND SPECIAL PURITY General requirements for methods of analysisMetals of high and special purity. |
GOST Instead |
Edition with Amendments No. 1, 2 approved in September 1982, June 1987 (ICS 1−83, 9−87).
The decision of the State standards Committee of the Council of Ministers. Of the USSR of January 11, 1977, No. 65 date of introduction set
01.01.1978
1. This standard applies to metals and high purity in which the amount of specified impurities is not more than 0.001%, and establishes General requirements for methods of analysis.
The standard complies ST SEV 2002−79 in part of metals of high purity.
(Changed edition, Rev. No. 1, 2).
2. (Deleted, Rev. No. 1).
3. Samples for analysis are produced according to normative-technical documentation for specific products.
3A. For the analysis used methods in which the detection limit determined by the impurities of 0.3 — 1.0 order (depending on the error of the method applied) below the values permissible concentration specified in the standards for the metals of high and special purity of specific brands.
Calculation of detection limit and sensitivity is given in the Appendix.
(Added, Rev. No. 1).
4. The contents of the designated impurities in the sample find not less than two batches. If necessary, to reduce the random component of error analysis, caused by the scatter of results of parallel measurements of the impurity in the sample, the number of batches of the sample increases to 3 — 4. If necessary, to reduce the random component of error of the average impurity content caused by the inhomogeneity of samples, select a few samples and find the arithmetic mean of the results of parallel measurements for all samples.
If necessary to control the spread of the results of parallel measurements of impurities in a sample, the method of analysis reglamentary with a specified confidence probability P = 0,95 allowable difference specified number of results of parallel measurements (the difference between the largest and smallest of them, but with a logarithmic normal distribution — the ratio of the largest to smallest). When the divergence of the results of parallel measurements more permissible definition of repeated.
The final result of the analysis, for methods, characterized by a logarithmic normal distribution of the results of parallel measurements, take the geometric mean of the results of parallel measurements. If the standard deviation of the results of determinations less than 10%, then accept or geometric mean, or arithmetic average of the results of parallel measurements.
Full discrepancy of the results of the parallel definitions should not exceed the values indicated in the specific standard for method of analysis to be rounded according to ST SEV 543−77 to the number of significant digits specified in the specific standard.
The numerical values of the result of the analysis should end with a figure the same category as the value characteristics of the measurement error.
5. Simultaneously with the analysis under the same conditions is carried out at least two control experiments to determine the amendments, taking into account the content of impurities in the reagents, and it is entered in the result of the determination.
Control of the correctness of the results of the analysis carried out using the state standard samples (GSO) at least once a month, and every time you replace reagents and solutions, after long interruptions and other changes that affect the results of the analysis.
The content of the controlled component in WITH, and the sample must not vary by more than two times, find it among parallel definitions set a specific standard for method of analysis.
The difference between the smallest and largest of results of parallel measurements of a standard sample shall not exceed the permissible differences given in the particular standard on method of analysis.
In the absence of a standard sample using the method of additives. Standard solution added to the sample of the analyzed material, take in the amount approximately corresponding to the half of the content is determined by the component.
The amount of additive is calculated as the difference between the found content of a component in the sample with addition and the result of the analysis of the sample without additives.
4, 5. (Changed edition, Rev. No. 1, 2).
6. For the preparation of solutions and tests used distilled water according to GOST 6709−72, further purified by distillation in quartz apparatus or ionization column, unless other requirements in the standard methods of analysis.
The used reagents must be chemically pure (hç). If you need ultra-pure reagents (OS. h), it must be in the standard methods of analysis.
Acid before application should be distilled in apparatus made of quartz. If for purification of acids and reagents required special methods, it is specified in standard methods of analysis.
The content of impurities in the metals used for the preparation of standard solutions and sample comparison, should be 5 — 10 times less than the permissible content of each of the designated impurities in the analyzed metal.
(Changed edition, Rev. No. 1).
6A. To build a calibration curve requires at least five calibration points. Each point is based on the arithmetic mean results of three parallel measurements. When constructing a calibration curve from the x-axis postpone concentration, or the concentration or the mass of an element in a specific amount, and the ordinate is the measured value, or a function of it.
(Added, Rev. No. 1).
7. In the expression «diluted 1:1, 1:2», etc. the first digits indicate the volume of the acid, or any solution, the second volume of the water.
8. Weighing of batches produced with the maximum error of 0.0002 g.
9. Laboratory volumetric ware: pipette, burette, flask — should match the first or second accuracy class according to GOST 1770−74 and NTD.
10. The analysis should be excluded the effect of dust, gaseous contaminants or particles from other samples analysed in the same room. In applying methods of analysis with very low detection limits, all work is carried out in boxes or in the workplace, ventilated filtered air or purified gas. Supply and exhaust ducts shall be constructed of vinyl plastic and isolated from the overall system. In the block clean rooms it is necessary to create superfluous pressure of 19.6 — 29.4 PA (2 — 3 mm of water. calendar). Block clean rooms separated from the rest of the sealed gateway with the flow of filtered air.
As the heating device for sample digestion and evaporation of solutions, use infrared lamp.
Working devices and laboratory equipment shall not have bare metal surfaces. In small laboratory equipment (tripods, holders, spatulas) structural metals and weak corrosive materials should be replaced with plastic, quartz, graphite. Metal parts which cannot be removed or replaced, should be isolated colouring, epoxy resins, silicone varnish or plastic coating with periodic renewal of the coating. If necessary special working conditions, then this is indicated in the standard methods of analysis.
Required to wear work clothes: gown and cap or kerchief (nylon, polyester, viscose), Slippers (skin, leather). For each employee should have two or three sets of work clothes and change it at least twice a week.
Required to conduct daily wet cleaning of workplaces, once every two weeks — the entire premises.
Workplaces should be provided with the air cleanliness class (gas) 1000 (not more than 35 particles of size 0.5 microns per 1 DM3).
9, 10. (Changed edition, Rev. No. 1).
11. Laboratory glassware for sample preparation and storage of solutions should be made of quartz, platinum, graphite, PTFE, Teflon, or polyethylene.
The dishes should be boiled in a solution of hydrochloric acid 6 mol/DM3. In the presence of organic impurities it is necessary to add 0.15% of perhydrol. For degreasing quartz, glass and for pre-cleaning oxidation-resistant organic polymer surfaces used alkaline solution of perhydrol, introducing ammonia to pH 11. For wiping the scales, scalpels, tweezers, knives, hour glasses and the workplace use ethanol technical rectified according to GOST 18300−87.
(Changed edition, Rev. No. 1, 2).
APP
Recommended
Calculation of detection limits and sensitivity
The detection limit determined by the impurities is calculated from the average of 20 measurements, which are obtained when carrying out control experiments in the same laboratory by one person under identical conditions (instruments, reagents), and three-time valuation of mean-square deviation values of these measurements according to the formula
where is the value measurement at the border of detection;
— the average value of the measurements in the control experiments;
Scounter. — evaluation of the standard deviation of the measurements during the control experiments.
The detection limit is calculated by the formula
WithPCH = K (Xcounter.+ 6 Scounter.),
whereFD is the detection limit;
K — ratio measured value to the concentration value.
(Added, Rev. No. 1).
