GOST 15027.16-86
GOST 15027.16−86 Bronze without tin. Methods for determination of cadmium (Change No. 1)
GOST 15027.16−86
Group B59
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Methods for determination of cadmium
Tinless bronze.
Methods for determination of cadmium
AXTU 1709
Date of introduction 1987−01−01
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
3. INTRODUCED FOR THE FIRST TIME
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced | Section number, paragraph, sub-paragraph |
| GOST 1467−93 |
2.2; 3.2 |
| GOST 3118−77 |
2.2 |
| GOST 3760−79 |
3.2 |
| GOST 3773−72 |
3.2 |
| GOST 4204−77 |
3.2 |
| GOST 4461−77 |
2.2; 3.2 |
| GOST 5457−75 |
2.2 |
| GOST 6563−75 |
3.2 |
| GOST 11293−89 |
3.2 |
| GOST 18175−78 |
Chapeau |
| GOST 25086−87 |
1.1, 2.4.2 b, 3.4.4 |
5. The expiration time limit is removed by the Resolution of Gosstandart of the USSR from
6. EDITION with Change No. 1, approved in October 1991 (IUS 1−92)
This standard establishes the atomic absorption and polarographic methods for the determination of cadmium (at a mass fraction of cadmium from 0.1% to 1.5%) in the tin bronze according to GOST 18175.
The standard fully complies ST SEV 5005−85.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 when two parallel definitions.
2. ATOMIC ABSORPTION METHOD
2.1. The essence of the method
The method is based on dissolving the samples in nitric acid and measuring the atomic absorption of cadmium in the flame acetylene-air at a wavelength of 228,8 nm.
2.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with all accessories.
A radiation source for cadmium.
Acetylene according to GOST 5457.
Nitric acid according to GOST 4461, diluted 1:1.
Hydrochloric acid according to GOST 3118, 2 mol/DMsolution.
Cadmium brand KDO according to GOST 1467.
Standard solutions of cadmium.
Solution a: 1 g of the cadmium is dissolved in 30 cmof a solution of nitric acid, the solution was boiled to remove oxides of nitrogen, cooled, placed in a volumetric flask with a capacity of 1000 cm
, made up to the mark with water and mix.
1 cmof the solution contains 0.001 g of cadmium.
Solution B: 25 cmsolution And placed in a volumetric flask with a capacity of 500 cm
, add 20 cm
of a hydrochloric acid solution, made up to the mark with water and mix.
1 cmof a solution of 0.00005 g contains cadmium
I.
2.3. Analysis
2.3.1. Weighed samples weighing 0.5 g were placed in a glass with a capacity of 250 cm, add 20 cm
of a solution of nitric acid and dissolve in the cold and then when heated. After dissolving, the solution was boiled to remove oxides of nitrogen, diluted with water to a volume of 50 cm
, transferred to a volumetric flask with a capacity of 250 cm
, made up to the mark with water and mix. In a volumetric flask with a capacity of 100 cm
is taken aliquot part of the solution in accordance with the table.1 add 10 cm
of hydrochloric acid, made up to the mark with water and mix.
Table 1
Mass fraction of cadmium, % |
The volume aliquote part of the solution, cm |
| From 0.1 to 0.8 |
25 |
| SV. Of 0.8 «to 1.5 |
10 |
Measure the atomic absorption of cadmium in parallel in the sample solution, the solution control experience and solutions to build a calibration curve at a wavelength of 228,8 nm in the flame acetylene — air. The concentration of cadmium found by the calibration schedule.
2.3.2. Construction of calibration curve
In eight of the nine volumetric flasks with a capacity of 100 cmplaced: 1,0; 2,0; 3,0; 4,0; 5,0; 6,0; 7,0 and 8.0 cm
of a standard solution of cadmium, which corresponds to 0,05; 0,10; 0,15; 0,20; 0,25; 0,30; 0,35 and 0.40 mg of cadmium. To all flasks add 10 cm
of hydrochloric acid, made up to the mark with water and mix. Measure the atomic absorption of cadmium immediately before and after measuring the absorbance of the sample solution. According to the obtained values build the calibration graph.
2.4. Processing of the results
2.4.1. Mass fraction of cadmium (a) in percent is calculated by the formula
where is the concentration of cadmium in the sample solution found by the calibration schedule, g/cm
;
— cadmium concentration in the solution in the reference experiment, was found in the calibration schedule, g/cm
;
— the volume of the final sample solution, cm
;
— the weight of the portion corresponding to aliquote part of the solution, g
.
2.4.2. Discrepancies in the results of parallel definitions should not exceed the values permitted by the divergence (
the rate of convergence) as shown in table.2.
Table 2
| Mass fraction of cadmium, % |
|
|
| From 0.1 to 0.8 incl. |
0,03 | 0,04 |
| SV. Of 0.8 «to 1.5 « |
0,08 | 0,11 |
(Changed edition, Rev. N 1).
2.4.2. Discrepancies in the results analysis, 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 specified in table.2.
2.4.2 b. Control of accuracy of analysis results is carried out by additives or by comparison of the results obtained of the polarographic method, in accordance with GOST 25086.
2.4.2 a, 2.4.2 b. (Added, Rev. N 1).
2.4.3. The differences in the assessment of the quality of the bronzes, the determination of cadmium is carried out by atomic absorption method.
3. POLAROGRAPHIC METHOD
3.1. The essence of the method
The method is based on dissolving the sample in nitric acid, the electrolytic release of copper and polarographic determination of cadmium in ammonia-chloride background in the interval of potentials from minus 0.6 to minus 1.0 V relative to a saturated calomel electrode.
3.2. Apparatus, reagents and solutions
Polarograph DC or AC with all accessories.
Electrolysis installation DC.
Platinum electrodes according to GOST 6563.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 4204, diluted 1:4.
Ammonia water according to GOST 3760.
Ammonium chloride according to GOST 3773.
Sodium sanitarily crystal.
Gelatin food according to GOST 11293.
Solutions background:
for polarography DC: 100 g of ammonium chloride and 50 g semitecolo sodium dissolved in 500 cmof water; 0.5 g of gelatin dissolved in 50 cm
of hot water. After cooling, combine the two solutions, add 100 cm
of ammonia solution and add water to volume 1000 cm
;
for polarography AC: 100 g of ammonium chloride dissolved in 500 cmof water, add 100 cm
of ammonia solution and add water to volume of 1000 cm
.
The solutions were prepared before use.
Cadmium brand KDO according to GOST 1467.
A standard solution of cadmium: 1. cadmium is dissolved in 30 cmof a solution of nitric acid, the solution was boiled to remove oxides of nitrogen, cooled, placed in a volumetric flask with a capacity of 1000 cm
, made up to the mark with water and mix.
1 cmof the solution contains 0.001 g of kad
MIA.
3.3. Analysis
Weighed samples weighing 0.5 g were placed in a glass with a capacity of 250 cm, add 20 cm
of a solution of nitric acid and dissolved first in cold and then when heated. After dissolving, the solution was boiled to remove oxides of nitrogen, diluted with water to a volume of 150 centimeters
, add 7 cm
of sulfuric acid solution and produce electrodeposited copper when a current of 1.5−2.0 A simultaneous mixing of the solution. The solution after electrolysis was evaporated to a volume of 20 cm
, cooled, neutralized with ammonia solution on the paper of the Congo and add 10 cm
of ammonia solution in excess. The solution was transferred to a volumetric flask with a capacity of 100 cm
, add 50 cm
of the solution of the background and topped to the mark with water. After 5 min, the part of the solution is placed in the polarographic vessel and the relevant sensitivity of the instrument determine the wave height of the cadmium in the range of potentials from minus 0.6 to minus 1.0 V. in Parallel, determine the height of a wave of cadmium in the sample solution with the addition of a standard solution of cadmium. The value of the standard additives is chosen so that the height of a wave of cadmium 1.5−2 times the height of a wave of cadmium for mortar samples
s.
3.4. Processing of the results
3.4.1. Mass fraction of cadmium (a) in percent is calculated by the formula
where 
cm
) of a standard solution of cadmium with concentration (
g/cm
), g;
— the height of a wave of cadmium, corresponding to the sample solution, mm;
— the height of a wave of cadmium, corresponding to the sample solution with the addition of a standard solution, mm;
— the weight of the portion of the sample,
G.
3.4.2. Discrepancies in the results of parallel definitions should not exceed the values permitted by the divergence (
the rate of convergence) as shown in table.2.
(Changed edition, Rev. N 1).
3.4.3. Discrepancies in the results analysis, 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 specified in table.2.
3.4.4. Control of accuracy of analysis results is carried out by additives or by comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.
3.4.3,
