GOST 13938.9-78
GOST 13938.9−78 Copper. Methods for determination of silver (with Amendments No. 1, 2, 3)
GOST 13938.9−78
Group B59
INTERSTATE STANDARD
COPPER
Methods for determination of silver
Copper. Methods for determination of silver
AXTU 1709
Date of introduction 1979−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
G. P. Giganov, E. M. Peneva, A. A. Blyahman, E. D. Shuvalov, A. N. Savelieva
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 13938.9−68
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph |
| GOST 1277−75 |
2.2 |
| GOST 3117−78 |
2.2 |
| GOST 3118−77 |
2.2; 3.2 |
| GOST 3760−79 |
2.2 |
| GOST 4160−74 |
2.2 |
| GOST 4204−77 |
2.2 |
| GOST 4461−77 |
2.2; 3.2 |
| GOST 4520−78 |
3.2 |
| GOST 5457−75 |
3.2 |
| GOST 5644−75 |
2.2 |
| GOST 6836−80 |
3.2 |
| GOST 10652−73 |
2.2 |
| GOST 11125−84 |
3.2 |
| GOST 11293−89 |
2.2 |
| GOST 13938.1−78 |
1 |
| GOST 20448−90 |
3.2 |
5. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
6. REPRINT (November 1999) with Amendments No. 1, 2, 3, approved in April 1983, June 1985, April 1988 (ICS 7 to 83, 8−85, 7−88)
This standard sets the photometric and atomic absorption methods for the determination of silver in copper (at a mass fraction of silver from 0.001 to 0.004%).
1. GENERAL REQUIREMENTS
General requirements for methods of analysis and safety requirements when performing tests according to GOST 13938.1.
Sec. 1. (Changed edition, Rev. N 3).
2. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF SILVER
2.1 the essence of the method
The method is based on the formation of multicomponent painted the joints silver-bromopyrogallol red-orthophenanthroline-gelatin*. Measure the optical density at a wavelength of 635 nm.
______________
* In this case, gelatin is not a stabilizer and is part of the connection.
Silver from copper, and interfering impurities are separated in the form of bromide of silver in conjunction with bromide of thallium (I).
2.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer with all accessories.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 4204, diluted 1:1, 2 n solution.
Hydrochloric acid according to GOST 3118, 1 n solution.
The ammonium nitrate.
Ammonia water according to GOST 3760, diluted 1:5.
Bromopyrogallol red (BOD); of 0.0002 M solution: 0,115 g of BOD is dissolved in 1 DMof water.
Orthophenanthroline, a 0.02 M solution of 3.96 g dissolved in 1 DMof water.
Ammonium acetate according to GOST 3117, a solution of 200 g/DM.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid, 2-water (Trilon B) according to GOST 10652, 0.1 M solution: 37,22 g of salt dissolved in 1 DMof water.
Gelatin food according to GOST 11293, solution 2.5 g/l; freshly prepared.
Potassium bromide according to GOST 4160, a solution of 5 g/DM.
Sanitarily anhydrous sodium GOST 5644.
Thallium sulfate (I), a solution of 10 g/DM.
Paper indicator, universal.
Irrigation solution; prepared as follows: 20 cmof potassium bromide solution and 50 cm
of sulphuric acid diluted 1:1, mix and add water to 400 cm
.
Silver nitrate according to GOST 1277.
Solutions of silver standard.
Solution A, prepared as follows: 0,1574 g of silver nitrate is placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.
1 cmof the solution contains 1 mg of silver.
Solution B is prepared as follows: 5 cmsolution And placed in a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof solution contains 50 micrograms of silver.
Solution; prepared as follows: 10 cmof solution B is placed in a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof solution contains 5 micrograms of silver.
All silver solutions should be stored in a dark place.
(Changed edition, Rev. N 3).
2.3. Analysis
2.3.1. The sample weighing 1.0 g was placed in a conical flask with a capacity of 250 cm, add 20 cm
of nitric acid, diluted 1:1. After the violent reaction solution is heated until complete dissolution of copper. The solution is cooled, add 10 cm
sulphuric acid diluted 1:1, and evaporated to release vapors of sulfuric acid. If the solution is painted in yellow color (organic), content in a flask, add ammonium nitrate (tip of spatula) and heated to a decolorizing solution. The contents of the flask cooled, the walls of the flask is washed with 5−7 cm
of water and heating was continued until the vapors escaping sulfuric acid. This operation is repeated two times. Residual volume of sulfuric acid should be about 2 cm
. The contents of the flask cool, add 10 cm
of water and heated to boiling. The solution was cooled, the insoluble precipitate was filtered on a medium density filter, place the filtrate in a beaker with a capacity of 50 cm
, the filter was washed with water, in small portions. The volume of filtrate and wash water should not exceed 20 cm
.
The solution is poured 5 cmof a solution of sulphate of thallium and with stirring to 5 cm
of potassium bromide solution. The contents of the beaker for 30 min, periodically stirred, and then leave for 3 hours.
The precipitate was filtered off on a tight filter and washed six times with wash liquid portions of 5 cm. The precipitate is washed with water in a glass, which conducted the deposition, add 2 cm
of sulphuric acid diluted 1:1, and is evaporated until the appearance of sulphuric acid fumes; add 1−2 drops of nitric acid (to destroy the bromide, and removing bromine) and continue to heat until the appearance of sulphuric acid fumes.
The contents of the Cup is cooled, washed walls 5−7 cmof water and the solution is evaporated to release vapors of sulfuric acid. This operation is repeated twice and then the solution is evaporated to a small volume (1−2 drops sulfuric acid). The contents of the beaker cool, add 10 cm
of water, 0.1 g of sodium semitecolo and boil for 1 min. the Solution was cooled, added to 2 cm
of the solution Trilon B ammonia solution, diluted 1:5, the pH of the solution should be 4 (the pH of the test solution on the indicator paper). Then add 2cm
of a solution of ammonium acetate (the pH of the solution should be about 6), 2 cm
of mortar phenantroline, 1 cm
of gelatin solution, 2 cm
of mortar bromopyrogallol red. After addition of each reagent the solution was stirred. The solution was transferred to volumetric flask with a capacity of 25 cm
, top up to the mark with water and mix. Measure the optical density of the solution at a wavelength of 635 nm in a cuvette with an optimum thickness of the layer.
Solution comparison when measuring optical density of the solution is conducted through all stages of analysis, starting with the deposition and containing all reagents with the exception of silver. A lot of silver set of the calibration schedule, constructed as described in section
2.3.2. Building a graded graphics
In a glass with a capacity of 50 cmis placed 0; 1,0; 2,0; 4,0; 6,0 and 8,0 cm
standard solution, which corresponds to 0; 5,0; 10,0; 20,0; 30,0 40,0 µg and silver, add 2 cm
of sulphuric acid diluted 1:1, and all operations are carried out as specified in clause 2.3, including the stage of deposition after the step of deposition.
According to the obtained values of optical density of solutions and their corresponding silver content build the calibration graph.
(Changed edition, Rev. N 1).
3. ATOMIC ABSORPTION METHOD OF DETERMINING SILVER
3.1. The method is based on dissolving the samples in nitric acid with addition of hydrochloric acid or nitrate of mercury and the measurement of the absorption lines of silver with the introduction of hydrochloric acid or nitric acid solutions in the flame acetylene-air.
(Changed edition, Rev. N 3).
3.2. Apparatus, reagents and solutions
Spectrophotometer, atomic absorption, comprising a lamp with a silver hollow cathode, burner flame: acetylene-air or propane-butane-air and spray system.
Acetylene according to GOST 5457.
Propane-butane according to GOST 20448.
Air compressor.
Water bidistilled.
Hydrochloric acid according to GOST 3118.
Nitric acid according to GOST 4461, diluted 1:1 and a solution of 0.1 mol/DM.
Nitric acid, OS.CH., (no chlorine) according to GOST 11125.
Mercury (II) nitrate 1-water according to GOST 4520, a solution of 25 g/DMin the solution nitric acid 0,1 mol/DM
.
Copper, standard samples for the spectral analysis of the No. 308 and No. 309 in the state Register No. 217, containing 25,5·1018.6·10
% of silver, respectively. It is possible to apply electrolytic copper with an established silver content.
The copper solution 100 g/l: 10.0 g of the standard sample N N 308 or 309 was dissolved with heating in 70 cm
of nitric acid, diluted 1:1, and the solution is evaporated to remove the bulk of the acid. Then add 10 cm
of water and heated to dissolve the salts. The solution was cooled and added to 16 cm
of hydrochloric acid. The solution was transferred to volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
10 cmof copper solution contains: 25,5 mkg of silver when using a standard copper sample No. 308 and 18.6 g of silver when using the standard sample N 309.
Silver GOST 6836*.
_______________
* On the territory of the Russian Federation GOST 6836−2002. — Note the manufacturer’s database.
Solutions of silver standard.
Solution A, prepared as follows: 0.1 g of silver are dissolved in 5 cm.of nitric acid of high purity, the solution was transferred to volumetric flask with a capacity of 1 DM
, made up to the mark with bidistilled water and stirred. The solution was stored in a dark place.
The same solution can be prepared as follows: 0.1 g of silver are dissolved in 25 cmof a solution of nitric acid (2:1), add 5 cm
of a solution of nitrate of mercury and heated to remove oxides of nitrogen. The solution was then cooled, placed in a volumetric flask with a capacity of 1000 cm
, is diluted to the mark with bidistilled water and stirred. The solution was stored in a dark place.
1 cmof the solution contains 0.1 mg of silver.
Solution B is prepared as follows: 10 cmof solution A is placed in a volumetric flask with a capacity of 100 cm
, made up to the mark with bidistilled water and stirred. Solution store no more than 5 hours.
The same solution can be prepared as follows: 10 cmof solution A is placed in a measuring flask with volume capacity of 1000 cm
, pour 5 cm
of a solution of mercurous nitrate and 10 cm
of nitric acid (1:1), dilute to the mark with bidistilled water and stirred.
1 cmof the solution contains 0.01 mg of silver.
(Changed edition, Rev. N 3).
3.3. Analysis
3.3.1. A sample of copper with a mass of 1.0 g was dissolved with heating in 10 cmof nitric acid, diluted 1:1, and the solution is evaporated to wet salts. Then add 10 cm
of water and heated to dissolve the salts. The solution was cooled and added to 16 cm
of hydrochloric acid. The solution was transferred to volumetric flask with a capacity of 100 cm
, made up to the mark and mix. The resulting copper solution sprayed into the flame of atomic absorption spectrophotometer and measure the absorbance in the flame at a wavelength of 328,1 nm.
At the same time conducting follow-up experience with all the applied reagents. The value of the optical density of the solution in the reference experiment is subtracted from the value of the optical density of the analyzed solution.
Weight of silver in the solution set for the calibration schedule.
Allowed to determine the mass fraction of silver to use addition method.
(Changed edition, Rev. N 1, 3).
3.3.1. A sample of copper with a mass of 1.0 g was placed in a beaker with a capacity of 100 cm, flow 10 cm
of nitric acid, diluted 1:1, and 2 cm
of a solution of nitrate of mercury. Heated to dissolve the sample. The solution is then cooled, placed in a volumetric flask with a capacity of 100 cm
, is diluted to the mark with water and mix.
Measure the absorption lines of silver in the flame of acetylene-air at a wavelength of 328,1 nm, together with the solutions in the reference experiment and for the construction of calibration curve.
Allowed simultaneous determination of the analyzed solution of zinc (from 0.0005 to 0,006%), Nickel (from 0.1 to 0.5%), lead (from 0.005 to 0.06%) and iron (from 0.01 to 0.06%).
(Added, Rev. N 3).
3.3.2. Construction of calibration curve
In a volumetric flask with a capacity of 100 cmis placed 0; 1,0; 2,0; 3,0 and 4,0 cm
standard silver solution B, 10 cm
of copper nitrate, 16 cm
of hydrochloric acid, made up to the mark with water and mix. Allowed preparation of solutions in the following way. In a volumetric flask with a capacity of 100 cm
placed at 10 cm
of nitric acid, diluted 1:1, and 2 cm
of a solution of nitrate of mercury. Then in the flask is poured sequentially 0; 1,0; 2,0; 3,0; 4,0 and 5,0 cm
standard solution B, dilute to the mark with water and mix.
The resulting solutions contain 19, 29, 39, 49 and 59 mg of silver when you use a copper solution prepared from the standard sample N 309, or 26, 36, 46, 56 and 66 mcg of silver when you use a copper solution prepared from a standard sample No. 308.
Next, carry out analysis as specified in paragraph 3.3.
The prepared solutions photometrist on atomic absorption spectrophotometer. According to the obtained values of optical density of solutions and their corresponding silver content build the calibration graph.
(Changed edition, Rev. N 3).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of silver () in the percentage of photometric and atomic absorption determination is calculated by the formula
where is the mass of silver was found in the calibration schedule, mcg;
— weight of copper,
4.2. Discrepancies in the results of two parallel measurements and the two tests should not exceed the values given in the table.
| Mass fraction of silver |
The absolute maximum discrepancy, %, results | |
| parallel definitions |
tests | |
| From 0,0010 to 0.0025 incl. |
0,0003 |
0,0004 |
| SV. 0,0025 «0,0050 « |
0,0005 |
0,0007 |
(Changed edition, Rev. N 3).
4.3. The differences in the assessment of mass fraction of silver used atomic absorption method.
(Added, Rev. N 3).
