GOST 15027.5-77
GOST 15027.5−77 Bronze without tin. Methods for determination of Nickel (with Amendments No. 1, 2)
GOST 15027.5−77
Group B59
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Methods for determination of Nickel
Non-tin bronze.
Methods for the determination of nickel
AXTU 1709
Date of introduction 1979−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 15027.5−69
4. The standard fully complies ST SEV 1535−79. Standard corresponds to ISO 4742−84 in part of bronze without tin
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph, sub-paragraph |
| GOST 8.315−97 |
2.4.4.1, |
| GOST 199−78 |
2.2, 4.2 |
| GOST 493−79 |
Chapeau |
| GOST 614−97 |
Chapeau |
| GOST 849−97 |
3.2, 4.2, 5.2 |
| GOST 2210−73 |
2.2 |
| GOST 3118−77 |
2.2, 4.2, 5.2 |
| GOST 3652−69 |
2.2 |
| GOST 3760−79 |
2.2, 4.2 |
| GOST 4166−76 |
4.2 |
| GOST 4204−77 |
2.2, 3.2, 5.2 |
| GOST 4328−77 |
3.2, 4.2 |
| GOST 4461−77 |
2.2, 3.2, 4.2, 5.2 |
| GOST 4951−79 |
2.2 |
| GOST 5456−79 |
4.2 |
| GOST 5817−77 |
2.2 |
| GOST 5828−77 |
2.2, 3.2, 4.2 |
| GOST 5837−78 |
4.2 |
| GOST 5841−74 |
2.2, 3.2 |
| GOST 5845−79 |
3.2 |
| GOST 6563−75 |
2.2 |
| GOST 6691−77 |
2.2, 3.2 |
| GOST 10484−78 |
2.2, 3.2, 5.2 |
| GOST 10929−76 |
4.2 |
| GOST 10527.1−77 |
2.3.1, 2.3.2, 3.3.1, 3.3.2 |
| GOST 18175−78 |
Chapeau |
| GOST 18300−87 |
2.2, 4.2 |
| GOST 20478−75 |
3.2 |
| GOST 22867−77 |
2.2, 3.2 |
| GOST 23932−90 |
2.2 |
| GOST 25086−87 |
1.1, 2.4.4, 3.4.4, 5.4.4 |
6. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
7. EDITION with Amendments No. 1, 2 approved in February 1983, March 1988 (IUS 6−83, 6−88)
This standard specifies the gravimetric method (with a mass fraction of Nickel from 0.5% to 35%), photometric and atomic absorption methods (with the mass fraction of Nickel from 0.05% to 7%) and extraction-photometric method (with mass fraction of Nickel from 0.05% to 1%) in the tin bronze according to GOST 18175, GOST and GOST 614 493.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 with the addition of sec. 1 GOST 15027.1.
(Changed edition, Rev. N 1, 2).
2. GRAVIMETRIC METHOD FOR THE DETERMINATION OF NICKEL
2.1. The essence of the method
The method is based on precipitation of Nickel in ammoniacal solution in the presence of tartaric or citric acid dimethylglyoxime in the form of insoluble chelation.
2.2. Apparatus, reagents and solutions
Crucibles filter according to GOST 23932 types of TF 3−20, 3−32.
Electrolysis setup with platinum electrodes according to GOST 6563.
Nitric acid according to GOST 4461 and diluted 1:1 and 1:99.
Ammonium nitrate according to GOST 22867, a solution of 100 g/DM.
Ammonium chloride according to GOST 2210, a solution of 200 g/DM.
Sodium acetate according to GOST 199.
Urea according to GOST 6691, a solution of 50 g/DM.
Hydrazine sulfate according to GOST 5841, a solution of 50 g/DM.
Bronchiology blue, alcoholic solution of 10 g/DM.
Ammonium vinocity according to GOST 4951.
Irrigation solution; prepared as follows: 10 g of ammonium Vinokurova dissolve in water, add 1 cmof ammonia and add water to 1000 cm
.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 4204, diluted 1:4 and 1:1.
Hydrochloric acid according to GOST 3118, a solution of 9 mol/DM.
Tartaric acid according to GOST 5817, a solution of 400 g/DM.
Citric acid according to GOST 3652, a solution of 400 g/DM.
Hydrofluoric acid according to GOST 10484.
Ammonia water according to GOST 3760 and diluted 1:50.
Deacetyltaxol (dimethylglyoxime) according to GOST 5828, alcoholic solution of 10 g/DM.
Rectified ethyl alcohol according to GOST 18300 and diluted 1:3.
(Changed edition, Rev.
N 1).
2.3. Analysis
2.3.1. For bronzes containing silicon
A portion of the bronze mass, given in table.1A, is placed in a platinum Cup, add 10 cmof nitric acid, diluted 1:1 and 1 cm
hydrofluoric acid. The dissolution is carried out under heating. Then add 5 cm
of sulphuric acid diluted 1:1, and the solution was evaporated prior to the allocation of white smoke of sulfuric acid. The residue is cooled, rinse the walls of the Cup with water and evaporated again until a white smoke of sulfuric acid. Salt is dissolved in water and the solution transferred to a beaker with a capacity of 300 cm
, dilute with water to 150 cm
, 8 cm add
boiled nitric acid, diluted 1:1, and produce copper by electrolysis according to GOST 15027.1.
Table 1A
| Mass fraction of Nickel, % | The mass of charge, g | The solution volume of sample, cm |
The volume aliquote part of the solution, cm |
| From 0.5 to 3 |
1 | All | - |
| SV. 3 «8 |
0,5 | All | - |
| «8» 12 |
1,0 | 250 | 50 |
| «12» 35 |
0,5 | 500 | 50 |
The electrolyte was transferred to a beaker with a capacity of 600 cm, dilute with water to 200 cm
and then carry out the analysis as described in section
2.3.2. For other bronzes
A portion of the bronze mass, given in table.1A, is placed in a beaker with a capacity of 300 cmand dissolved in 10 cm
of nitric acid, diluted 1:1, when heated. After complete dissolution of the sample rinse the walls of the glass with water and remove the oxides of nitrogen by boiling. Add 50 cm
of hot water, 20 cm
of hot ammonium nitrate solution and heated for 10 min. In case of allocation metalbands acid, the precipitate is filtered off and the filter cake washed 7−8 times with hot solution of nitric acid, diluted 1:99.
The solution was then diluted to 150 cmwater and produce copper and lead by electrolysis according to GOST 15027.1. When you are prompted during the electrolysis of pink coloring (oxidation of manganese) is added dropwise a solution of urea or hydrazine sulphate to a bleaching solution. The electrolyte or aliquot part of the solution (see table.1A) is transferred into a beaker with a capacity of 600 cm
and dilute with water to 200 cm
.
The solution was added 10 cmof a solution of tartaric acid, 25 cm
of a solution of ammonium chloride and neutralized with ammonia to slightly acid reaction (pH 4−5) on universal indicator paper or add a few drops of blue bromtimol and ammonia to alkaline reaction, and then dropwise nitric acid diluted 1:1, to change the color of the solution. The solution is heated to 70 °C, add 30 cm
dimethylglyoxime alcohol solution, 5 g sodium acetate, 2−3 cm
of ammonia to slightly alkaline reaction and incubated in a water bath for 2 hours (can leave overnight). The precipitate was filtered on a previously weighed filter crucible under suction. The precipitate is washed three times with hot solution of washing, six to eight times with hot water and finally twice with ethanol, diluted 1:3. The crucible with the precipitate is dried in a drying oven at 110−120 °C to constant weight.
(Changed edition, Rev.
N 1).
2.4. Processing of the results
2.4.1. Mass fraction of Nickel () in percent is calculated by the formula
where is the mass of sediment dimethylglyoximate Nickel, g;
0,2032 — conversion factor dimethylglyoximate of Nickel to Nickel; — the weight of the portion.
2.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
Table 2
| Mass fraction of Nickel, % |
|
|
| From 0.05 to 0.10 |
0,010 | 0,02 |
| SV. Of 0.10 «to 0.25 |
0,012 | 0,03 |
| «0,25» 0,5 |
0,02 | 0,05 |
| «0,5» 1,0 |
0,04 | 0,1 |
| «Of 1.0» to 3.0 |
0,05 | 0,1 |
(Changed edition, Rev. N 2).
2.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
2.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner, or by comparing the analysis results obtained by gravimetric and atomic absorption methods in accordance with GOST 25086.
2.4.3,
3. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF NICKEL
3.1. The essence of the method
The method is based on formation of Nickel coloured compounds with dimethylglyoxime in an alkaline medium in the presence of an oxidant and measuring the optical density of colored solution.
3.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 4204, diluted 1:4.
Hydrofluoric acid according to GOST 10484.
Potassium sodium vinocity according to GOST 5845 (Sagatova salt), a solution of 200 g/DM.
Sodium hydroxide according to GOST 4328, 2 mol/DMsolution.
Ammonium neccersarily according to GOST 20478, a freshly prepared solution of 100 g/DM.
Deacetyltaxol (dimethylglyoxime) according to GOST 5828, a solution of 10 g/DMin the solution of 2 mol/DM
sodium hydroxide.
Nickel brand H0 according to GOST 849.
Standard solutions of Nickel.
Solution A, prepared as follows: 0.2 g of Nickel dissolved in 20 cmof nitric acid, diluted 1:1. Nitrogen oxides are removed by boiling. The solution was transferred to volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
1 cmof the solution contains 0.0002 g of Nickel.
Solution B is prepared as follows: 25 cmsolution And placed in a volumetric flask with a capacity of 250 cm
, made up to the mark with water and mix. 1 cm
of solution B contains 0,00002 g of Nickel.
Ammonium nitrate according to GOST 22867, a solution of 100 g/DM.
Nitric acid according to GOST 4461, diluted 1:1 and 1:99.
Urea according to GOST 6691, a solution of 50 g/DM.
Hydrazine according to GOST 5841, a solution of 50 g/DM.
(Changed edition, Rev.
N 1, 2).
3.3. Analysis
3.3.1. For bronzes containing silicon
The weight of bronze weighing 0.5 g is placed in a platinum Cup, add 10 cmof nitric acid, diluted 1:1 and 1 cm
hydrofluoric acid. The dissolution is carried out under heating. Then add 5 cm
of sulphuric acid diluted 1:1, and the solution was evaporated prior to the allocation of white smoke of sulfuric acid.
The residue is cooled, rinse the walls of the Cup with water and evaporated again until a white smoke of sulfuric acid. Salt is dissolved with water and solution transferred to a beaker with a capacity of 300 cm, add 10 cm
of nitric acid, dilute with water to 50 cm
and produce copper by electrolysis according to GOST 15027.1.
The electrolyte transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with water, mix and then carry out the analysis as described in section 3.3.2
.
3.3.2. For bronzes all other brands
The weight of bronze weighing 0.5 g were placed in a glass with a capacity of 300 cmand dissolved in 10 cm
of nitric acid, diluted 1:1 with slow heating. After complete dissolution of the sample rinse the walls of the glass with water and remove the oxides of nitrogen by boiling, add 50 cm
of hot water and 20 cm
of hot ammonium nitrate solution, heated for 10 min in the case of sedimentation metalbands acid it is filtered off on a tight filter and washed precipitate on the filter with hot nitric acid, diluted 1:99, after which the precipitate was discarded. The solution was then diluted with water to 150 cm
, in the absence of lead in the alloy added 7 cm
of sulphuric acid, diluted 1:4, and produce copper by electrolysis according to GOST 15027.1. In the presence of lead in sulfuric acid is added after the separation of the main mass of lead by electrolysis. In the case of pink coloring in the process of electrolysis (oxidation of manganese) is added dropwise a solution of urea sulfate or hydrazine. The electrolyte transferred to a volumetric flask with a capacity of 250 cm
, and topped to the mark with water.
Depending on the content of Nickel in bronze taken aliquot part of the solution in accordance with the table.3.
Table 3
| Mass fraction of Nickel, % |
The volume aliquote part of the solution, cm |
The weight of the portion corresponding to aliquote part of the solution, g |
| From 0.05 to 0.25 |
25 | 0,05 |
| SV. 0,25 «0,5 |
10 | 0,02 |
| Of 0.5 to 7.0 |
5 | 0,01 |
Aliquot part of the solution (see table.3) is placed in a volumetric flask with a capacity of 100 cm, add 20−25 cm
of water and consistently poured 10 cm
of a solution of Rochelle salt, 15−20 cm
of sodium hydroxide solution, 10 cm
of a solution of ammonium naternicola 10 cm
dimethylglyoxime solution, made up to the mark with water and mix. Optical density of the solution measured on photocolorimeter with a green optical filter in a cuvette (3 cm for the mass concentration of Nickel up to 1%), cuvette (1 cm for the mass concentration of Nickel in excess of 1%) or on the spectrophotometer at a
=434 nm in a cuvette of 1 cm relative to the solution in the reference experiment.
Mass fraction of Nickel is calculated according to the calibration schedule.
(Changed edition, Rev. N 2).
3.3. Construction of calibration curve
3.3.3.1. In a volumetric flask with a capacity of 100 cmplaced 0; 1,0; 2,0; 3,0; 4,0; 5,0; 6,0 and 7.0 cm
standard solution B of Nickel, dilute with water to 20−25 cm
and further analysis are as indicated in claim
3.3.2. In a volumetric flask with a capacity of 100 cmplaced 0; 1,0; 1,5; 2,0; 2,5; 3,0 and 3.5 cm
standard solution A of Nickel, dilute with water to 20−25 cm
and further analysis are as indicated in claim
(Changed edition, Rev. N 2).
3.4. Processing of the results
3.4.1. Mass fraction of Nickel () in percent is calculated by the formula
where is the mass of Nickel was found in the calibration schedule g;
— the weight of the portion corresponding to aliquote part of the solution,
3.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
3.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
3.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner, or by comparing the results of analysis of the obtained photometric and atomic absorption or gravimetric methods in accordance with GOST 25086.
3.4.3,
4. EXTRACTION-PHOTOMETRIC METHOD FOR THE DETERMINATION OF NICKEL
4.1. The essence of the method
The method is based on the extraction of zheltooranzhevogo complex dimethylglyoximate Nickel chloroform and measuring the optical density of the extract.
4.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Nitric acid according to GOST 4461.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Ammonia water according to GOST 3760.
Sodium hydroxide according to GOST 4328, a solution of 200 g/DM.
Hydroxylamine hydrochloric acid according to GOST 5456, a solution of 10 g/DM.
Sodium Chernovetskiy, a solution of 200 g/DM.
Sodium acetate according to GOST 199, a solution of 200 g/DM.
Sodium vinocity acidic, GOST 5837, solution 100 g/DM.
Rectified ethyl alcohol according to GOST 18300.
Hydrogen peroxide according to GOST 10929.
Deacetyltaxol (dimethylglyoxime) according to GOST 5828, alcoholic solution of 10 g/DM.
Complexing solution is prepared as follows: mix 240 cmsolution Vinokurova acid sodium, 480 cm
of a solution of sodium acetate and 200 cm
of the solution servational sodium.
Sodium sulphate anhydrous according to GOST 4166.
Chloroform.
Nickel brand H0 according to GOST 849.
Standard solutions of Nickel.
Solution A, prepared as follows: 1 g of Nickel is dissolved in a beaker with a capacity of 250−300 cmin 20 cm
of hydrochloric acid diluted 1:1, and 10 cm
of hydrogen peroxide, added in small portions when the sample is completely dissolved, boil for 1 min to decompose excess hydrogen peroxide, cooled, and transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
1 cmof the solution contains 0.001 g of Nickel.
Solution B is prepared as follows: 10 cmof the solution And transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof a solution contains 0,000
1 g of Nickel.
4.3. Analysis
4.3.1. The sample of bronze with a weight of 1 g was placed in a beaker with a capacity of 250−300 cmand dissolved in 20 cm
of hydrochloric acid diluted 1:1, and 10 cm
of hydrogen peroxide added in small portions. When the sample dissolved completely, the solution was boiled for 1 min to decompose excess hydrogen peroxide. Then translate the solution into a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix. Aliquot part 10 cm
(when the mass fraction of Nickel up to 0.5%) or 5 cm
(when the mass fraction of Nickel from 0.5% to 1%) was placed in a separating funnel with a capacity of 250 cm
, dilute with water to 25 cm
and the solution basified with ammonia and then again acidified with hydrochloric acid diluted 1:1, to pH 6.5 on the indicator paper. Then add 5 cm
of a solution of hydroxylamine and 50 cm
complexing solution, shaking after each addition of the reagent. Then add 3 cm
of a solution dimethylglyoxime, shake 60, poured 20 cm
of chloroform and extracted for 40 s. After phase separation, painted in yellow chloroform solution is transferred into a flask with a capacity of 50 cm
containing 0.2 g of anhydrous sodium sulfate, and an aqueous solution repeat the extraction with 10 cm
of chloroform. The flask with the combined extract was topped up to the mark with chloroform, stoppered and mixed. Optical density of the solution measured on a spectrophotometer at a wavelength of 360 nm in a cuvette length of 1 cm or photoelectrocolorimeter at a wavelength of 413 nm in a cuvette of length 2, see Solution comparison is the chloroform layer control experience.
The Nickel content calculated for the calibration
graphics.
4.3.2. Construction of calibration curve
In the separating funnel is poured sequentially 0; 1; 2; 3; 4; 5 and 6 cmstandard solution B, add ammonia to alkaline reaction and then analysis are as indicated in claim
Solution comparison is the extract, prepared without the addition of a standard solution of Nickel.
4.4. Processing of the results
4.4.1. Mass fraction of Nickel () in percent is calculated by the formula
where is the mass of Nickel was found in the calibration schedule g;
— the weight of the portion of the sample corresponding to aliquote part of the solution,
4.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
4.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
3.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to claim
4.4.3,
5. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF NICKEL
5.1. The essence of the method
The method is based on measuring the absorption of light by atoms of Nickel, formed during the introduction of the analyzed solution in the flame acetylene-air.
5.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with a radiation source for Nickel.
Nitric acid according to GOST 4461 and diluted 3:2 and 1:1.
Hydrochloric acid according to GOST 3118 and solutions 2 and 1 mol/DM.
A mixture of acids, is prepared as follows: one volume of nitric acid mixed with three volumes of hydrochloric acid.
Hydrofluoric acid according to GOST 10484.
Sulfuric acid according to GOST 4204, diluted 1:1.
Nickel GOST 849 with a mass fraction of Nickel is not less than 99.9%.
Standard solutions of Nickel.
Solution A, prepared as follows: 0.5 g of Nickel is dissolved by heating in 20 cmof nitric acid, diluted 3:2, the solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm
and top up with water to the mark.
1 cmof the solution contains 0.0005 g of Nickel.
Solution B is prepared as follows: 20 cmsolution And transferred to a volumetric flask with a capacity of 100 cm
, add 10 cm
solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
1 cmof the solution contains 0.0001 g Nickel
I.
5.3. Analysis
5.3.1. For bronzes with a mass fraction of silicon to 0.05%.
A portion of the bronze mass, given in table.5, is placed in a beaker with a capacity of 250 cmand dissolved by heating in 10 cm
of a mixture of acids. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm
, rinse walls of beaker with a solution of 1 mol/DM
of hydrochloric acid and topped up to the mark with the same acid. When the mass fraction of Nickel in excess of 0.25% of 10 cm
of the solution transferred to an appropriate volumetric flask (see table 5) and then filled to the mark with a solution of 1 mol/DM
of hydrochloric acid.
Table 5
| Mass fraction of Nickel, % | The weight of the portion of the sample, g | The volume aliquote part of the solution, cm |
The volume of 2 mol/DM |
The volume of solution after dilution, see |
| From 0.05 to 0.25 |
1 | - | - | 100 |
| SV. Of 0.25 «to 1.5 |
1 | 10 | 10 | 100 |
| Is 1,5 7,0 |
0,5 | 10 | 25 | 250 |
Measure the atomic absorption of Nickel in the flame acetylene-air at a wavelength of 232,0 nm or 341,5 parallel to the calibration solutions.
5.3.2. For bronzes, with a mass fraction of silicon in excess of 0.05%
A portion of the bronze mass, given in table.5, is placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid, diluted 1:1, and 2 cm
hydrofluoric acid. After dissolution, add 10 cm
sulphuric acid diluted 1:1, and the solution was evaporated until a white smoke of sulfuric acid. The residue is cooled, rinse the walls of the Cup with water and evaporated again until a white smoke of sulfuric acid. The residue is cooled and dissolved in water when heated. The solution was transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark. When the mass fraction of Nickel in excess of 0.25% of 10 cm
of the solution transferred to an appropriate volumetric flask (see table 5), a solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
Measure the atomic absorption of Nickel, as specified in clause
5.3.3. Construction of calibration curve
In twelve of the thirteen volumetric flasks with a capacity of 100 cmis placed 1,0; 2.0; 4,0; 6,0 and 8,0 cm
standard solution B, and 2,0; 2,5; 3,0; 3,5; 4,0; 5,0 and 6.0 cm
of standard solution A. In all flasks add 10 cm
solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
Measure the atomic absorption of Nickel, as specified in clause
According to the obtained results build a calibration curve.
5.4. Processing of the results
5.4.1. Mass fraction of Nickel () in percent is calculated by the formula
where is the concentration of Nickel was found in the calibration schedule, g/cm
;
— the volume of the final sample solution, cm
;
— the weight of the portion contained in the final volume of the sample solution,
5.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
5.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
5.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner, or by comparing the results of analysis obtained by atomic absorption and photometric or gravimetric methods in accordance with GOST 25086.
5.4.3,
