GOST 741.4-80
STATE STANDARD OF THE USSR
COBALT
METHODS FOR DETERMINATION OF COPPER
COBALT
Methods for the determination of copper
GOST 741.4−80
Group B59
AXTU 1709
(AXTU introduced by the Change in N 1, approved. By the decree of Gosstandart of the USSR from
Replace GOST 741.4−69
The validity of
from July 1, 1981
prior to July 1, 1986
This standard establishes the atomic absorption and photometric methods for the determination of copper when the mass fraction of from 0.0005 to 0.15%.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 741.1−80.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
2. ATOMIC ABSORPTION METHOD
(when the mass fraction of copper from 0.0005 to 0.15%)
2.1. The essence of the method
The method is based on measuring atomic absorption of copper in the flame at a wavelength of 324,7 nm.
2.2. Apparatus, reagents and solutions
Spectrophotometer of atomic absorption with background correction.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
A radiation source for copper.
(paragraph added by the Change in N 2, approved. By the decree of Gosstandart of the USSR from
Acetylene in cylinders with reducer according to GOST 5457−75.
The compressor providing air pressure flame of about 2 ATM.
Nitric acid according to GOST 11125−84 or GOST 4461−77, solutions of 1:1 and 1:10.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
Ammonia water according to GOST 3760−79, a solution of 1:10.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
Chloroform according to GOST 20015−88.
(paragraph added by the Change in N 2, approved. By the decree of Gosstandart of the USSR from
The diethyldithiocarbamate lead, a solution of 0.1 g/dm3 in chloroform: 0.1 g of salt dissolved in 200 cm3 of chloroform and diluted with chloroform up to 1000 cm3.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Hydrogen peroxide according to GOST 10929−76.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
Universal indicator paper.
(paragraph added by the Change in N 2, approved. By the decree of Gosstandart of the USSR from
Cobalt grade FOR according to GOST 123−78; a solution of nitrate of cobalt free of copper: a portion of the cobalt with a mass of 10.00 g was dissolved in 70 cm3 of nitric acid solution 1:1, evaporated to wet salts, cooled, poured 50 cm3 of water and heated to dissolve the salts. The resulting solution was transferred to a separatory funnel with a capacity of 1000 cm3, diluted with water to 500 cm3 and establish a pH of 3 to 4 to universal indicator paper by adding ammonia solution 1:1 or a nitric acid solution of 1:10. Then pour 25 cm3 of solution of diethyldithiocarbamate lead in chloroform and extracted 2 min, the chloroform Layer, yellow in color, is decanted, extraction is repeated twice more, priliva 10 cm3 of diethyldithiocarbamate lead. A second extraction was carried out for 1 min., the third — 0.5 m. the Organic extract is discarded and the aqueous layer is poured into a porcelain Cup and evaporated to 10 to 15 cm3. Then pour 20 to 25 cm3 of nitric acid and 5 — to 10 cm3 of hydrogen peroxide. The solution treatment peroxide repeated three times and evaporated up to wet salts. After this solution was cooled, poured 50 cm3 of water, heated to dissolve the salts, again cooled, transferred to a volumetric flask with a capacity of 100 cm3 and topped to the mark with water.
(in edition of Changes N 1, approved. By the decree of Gosstandart of the USSR from
1 cm3 of the solution contains 0.1 g of cobalt.
(paragraph added by the Change in N 2, approved. By the decree of Gosstandart of the USSR from
Copper grade MO according to GOST 859−78.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
Standard solutions of copper.
Solution A: 0.5 g of copper is dissolved in 20 cm3 of nitric acid solution 1:1 when heated, boil to remove oxides of nitrogen. The solution was cooled and transferred to volumetric flask with a capacity of 1 dm3, made up to the mark with water and mix.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
1 cm3 of solution A contains g of copper.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Solution B: 10 cm3 of solution A is transferred to a volumetric flask with a capacity of 100 cm3, made up to the mark with water and mix.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
1 cm3 of solution B contains g of copper.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
2.3. Analysis
A portion of the cobalt is placed in a beaker with a capacity of 300 cm3, is dissolved when heated in nitric acid, diluted 1:1. The amount of sample amount of nitric acid given in table. 1.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Table 1
───────────────────┬─────────┬────────────┬────────────┬──────────
Mass fraction of copper,│Mass na-│Volume the nitrogen- │Volume measuring│Aliquota
% │good, g │Noah acid,│ flasks, cm3 │part, cm3
│ │cm3 │ │
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
09.01.1986 N 54)
───────────────────┼─────────┼────────────┼────────────┼──────────
From 0.0005 to 0.005│5 │50 │100 │Inall Rast-
│ │ │ │thief
SV. 0,005 «0,05 │1 │20 │100 │Ton the same
0,05 «0,15 │1 │20 │100 │10
After dissolution of the sample the excess nitric acid is removed by evaporation of solution to wet salts. The glass is slightly cooled, pour 10 to 15 cm3 of water, heated to dissolve the salts. The resulting solution was cooled, transferred to a volumetric flask with a capacity of 100 cm3, made up to the mark with water and mix.
(in edition of Changes N 1, approved. By the decree of Gosstandart of the USSR from
The resulting solution was cooled, transferred to a volumetric flask with a capacity of 100 cm3 and topped to the mark with water. When the mass fraction of from 0.05 to 0.15% take aliquot part 10 cm3 in a volumetric flask with a capacity of 100 cm3 and topped to the mark with water.
(in edition of Changes N 2, approved. By the decree of Gosstandart of the USSR from
Spray successively into the flame of the analyzed solutions, the calibration solutions, the solutions in the reference experiment and measure the values of the atomic absorption of copper at a wavelength of 324,7 nm.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
The copper concentration in the analyzed solutions found by the calibration schedule, adjusted for the concentration of copper in solution in the reference experiment.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
2.4. The construction of the calibration graph (when the mass fraction of copper from 0.0005 to 0.005%)
In a volumetric flask with a capacity of 100 cm3 is placed 0; 0,50; 1,00; 2,00; 5,00; 10,00 cm3 of standard solution B, which corresponds to (0; 0,25; 0,50; 1,00; 2,50; 5,00) g/cm3 of copper, pour the 50 cm3 of nitric acid cobalt and topped to the mark with water. The resulting solutions sprayed into the flame of acetylene-air in accordance with clause 2.3.
According to the obtained values of atomic absorption and their corresponding concentrations to build a calibration graph, adjusted for the value of atomic absorption calibration solution not containing copper.
(item 2.4 as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
2.5. The construction of the calibration graph (when the mass fraction of copper from 0.005 to 0.15%)
In a volumetric flask with a capacity of 100 cm3 is placed 0; 0,50; 1,00; 2,00; 5,00; 10,00 cm3 of standard solution B, which corresponds to (0, 0,25; 0,50; 1,00; 2,50; 5,00) g/cm3 of copper, made up to the mark with water and measure the atomic absorption of copper, as described above.
(clause 2.5 as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
2.6. Processing of the results
2.6.1. The mass percent of copper (X) in percent is calculated by the formula
,
where With is the concentration of copper in the sample solution, found by calibration schedule, g/cm3;
V — volume fotometricheskogo solution, cm3;
m — weight of cobalt, g.
(paragraph 2.6.1 as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
2.6.2. Allowable absolute discrepancies in the results of parallel measurements characterizing the convergence of the method (d), and the results of two analyses that characterize the reproducibility of the method (D), shall not exceed the values specified in table. 2.
Table 2
────────────────────────────┬─────────────────────────────────────
Mass fraction of copper, % │allowable Absolute differences, %
├───────────────────┬─────────────────
│ d │ D
────────────────────────────┼───────────────────┼─────────────────
From 0.0005 to 0.0008 inch incl. │Of 0.0002 │0,0003
SV. To 0,0008 0,0020 «│0,0004 │0,0004
«0,0020» 0,0040 «│0,0007 │0,0008
«0,0040» 0,0080 «│0,0012 │0,0015
«0,008» 0,020 «│0,002 │0,002
«0,020» 0,040 «│0,003 │0,003
«0,040» 0,100 «│0,005 │0,005
«0,10» 0,15 «│0,01 │0,01
(paragraph 2.6.2 as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
3. PHOTOMETRIC METHOD
(when the mass fraction of copper from 0.0005 to 0.15%)
3.1. The essence of the method
The method is based on measurement of absorption of complex compounds of copper by diethyldithiocarbamate lead after a preliminary separation by extraction.
(clause 3.1 as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
3.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer of any type.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
Nitric acid according to GOST 11125−84 or GOST 4461−77, solutions 3:2, 1:1, 1:10.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
Ammonia water according to GOST 3760−79, a solution of 1:9.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
The paragraph was removed. — Amendment No. 1, approved. By the decree of Gosstandart of the USSR from
Paper universal indicator.
Chloroform according to GOST 20015−74.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
The diethyldithiocarbamate lead, a solution of 0.1 g/dm3 in chloroform: 0.1 g of diethyldithiocarbamate lead is dissolved in 200 cm3 of chloroform and then diluted with chloroform to 1 dm3.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Copper grade MO according to GOST 859−78.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
The paragraph was removed. — Amendment No. 2, approved. By the decree of Gosstandart of the USSR from
Standard solutions of copper.
Solution A: 0.1 g of copper is dissolved in 10 cm3 of nitric acid, diluted 1:1, boil to remove oxides of nitrogen. The solution was then cooled, transferred to a volumetric flask with a capacity of 500 cm3, top up with water to the mark and mix.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
1 cm3 of solution A contains g of copper.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Solution B: 5 cm3 of solution A is transferred to a volumetric flask with a capacity of 200 cm3, top up with water to the mark and mix.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
1 cm3 of solution B contains g of copper.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
3.3. Analysis
A portion of the cobalt (see table. 2A) is dissolved in 15 — 30 cm3 of nitric acid solution 1:1, evaporated to a volume of 2 — 3 cm3, poured water and transferred into a measuring flask with a capacity of 100 cm3 and topped to the mark with water.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Table 2A
──────────────────────────┬────────────┬─────────────┬────────────
Mass fraction, % │Weight Nawa-│Volume measuring │ Aliquota
│CI, g │ flasks, cm3 │ part, cm3
──────────────────────────┼────────────┼─────────────┼────────────
To 0.001 incl. │2,0000 │100 │Inthe entire solution
SV. 0,001 «0,01» │0,5000 │100 │50
«0,01» 0,2 «│0,2000 │100 │25
«0,05» 0,15 «│0,2000 │100 │5
(table introduced by the Change in N 2, approved. Resolution Of Gosstandart
Of the USSR dated
When the mass fraction of copper of 0.001% the entire solution was transferred to a separatory funnel with a capacity of 250 cm3, diluted with water to 200 cm3 and establish a pH of 3 to 4 to universal indicator paper by adding ammonia solution 1:1, or nitric acid, a solution of 1:10. In the thus prepared solution is poured 10 cm3 of a solution of diethyldithiocarbamate lead in chloroform and extracted 2 min, the chloroform Layer, yellow in color, poured into a porcelain Cup or a glass (conical flask) with a capacity of 100 cm3. The aqueous layer is extracted twice more, priliva 5 cm3 of a solution of diethyldithiocarbamate lead. A second extraction was carried out for 1 min, the third is 0.5 m. If the last extraction the chloroform layer has a light yellow color, carried out the extraction with 5 cm3 of a solution of diethyldithiocarbamate lead for 0.5 min. Collected in a porcelain Cup organic extracts placed in a water bath and evaporated to dryness. The dry residue is treated with 5 cm3 of nitric acid solution 1:1 and again evaporated to dryness. Salt dissolved in 3 cm3 of nitric acid solution 1:10, the solution transferred to a separatory funnel with a capacity of 100 cm3, diluted with water to 50 cm3, set the pH of the solution 3 to 4 and extracted copper, as described above. The organic extract is collected in a volumetric flask with a capacity of 25 cm3 (so that water droplets do not hit the flask, separating funnel spout inserted a small cotton swab) and adjusted to the mark of the flask with chloroform.
(in edition of Changes N 1, approved. By the decree of Gosstandart of the USSR from
For the mass concentration of copper greater than 0.001% aliquot part of the solution (see table. 2A) transferred to a separatory funnel with a capacity of 100 cm3, diluted with water to 50 cm3, establish a pH of 3 to 4, as indicated above, pour the 10 cm3 of the solution of diethyldithiocarbamate lead in chloroform and extracted 2 min, the chloroform Layer, colored yellow, is poured into a measuring flask with a capacity of 25 cm3. The aqueous layer is extracted twice more, priliva 5 cm3 of a solution of diethyldithiocarbamate lead. A second extraction was carried out for 1 min, the third is 0.5 m. If the last extraction the chloroform layer has a light yellow color, spend another extraction with 5 cm3 of a solution of diethyldithiocarbamate lead for 0.5 min. combined in volumetric flask extracts of diethyldithiocarbamate copper diluted to the mark of the flask with chloroform.
(in edition of Changes N 1, approved. By the decree of Gosstandart of the USSR from
Measure the light absorption of the extract at a wavelength of 413 nm.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
As a solution comparison solution is used in the reference experiment.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
Mass of copper in the sample solution found by the calibrationschedule.
(as amended by Changes No. 2, approved. By the decree of Gosstandart of the USSR from
3.4. The construction of the calibrationgraph
In a separating funnel with a capacity of 100 cm3 taken 0; 0,50; 1,00; 3,00; 5,00; 7,00 cm3 of standard solution B, which corresponds to (0; 0,0025; 0,0050; 0,015; 0,025; 0,035) g of copper, pour water to a volume of 50 cm3 and then carry out the analysis in accordance with clause 3.3.
(paragraph 3.4 as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
3.5. Processing of the results
3.5.1. The mass percent of copper (X) in percent is calculated by the formula
,
where mass copper was found in the calibration schedule g;
— total volume of solution, cm3;
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
m — weight of cobalt, g;
V — aliquota part of the solution, cm3.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
3.5.2. Allowable absolute discrepancies in the results of parallel measurements characterizing the convergence of the method (d), and the results of two analyses that characterize the reproducibility of the method (D), shall not exceed the values given in table. 2.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
