GOST 22519.3-77
GOST 22519.3−77 Thallium. Method for the determination of silver (with Amendments No. 1, 2, 3)
GOST 22519.3−77
Group B59
STATE STANDARD OF THE USSR
THALLIUM
Method for the determination of silver
THALLIUM. Method for the determination of silver
AXTU 1709
Date of introduction 1978−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
A. P. Sychev, M. G. Sun, V. I. Lysenko, I. A. Romanenko, V. A. Kolesnikov
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
Change No. 3 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 4 dated 21.10.93)
The adoption voted:
| The name of the state |
The name of the national authority for standardization |
| The Republic Of Armenia |
Armastajad |
| The Republic Of Belarus |
Gosstandart Of Belarus |
| The Republic Of Kazakhstan |
Gosstandart Of The Republic Of Kazakhstan |
| The Republic Of Moldova |
Moldovastandart |
| Russian Federation |
Gosstandart Of Russia |
| The Republic Of Turkmenistan |
The main state inspection of Turkmenistan |
| The Republic Of Uzbekistan |
Standards |
| Ukraine |
Gosstandart Of Ukraine |
3. INTRODUCED FOR THE FIRST TIME
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
The number of the paragraph, subparagraph |
| GOST 61−75 |
2 |
| GOST 199−78 |
2 |
| GOST 2062−77 |
2 |
| GOST 3760−79 |
2 |
| GOST 4109−79 |
2 |
| GOST 4165−78 |
2 |
| GOST 4204−77 |
2 |
| GOST 4461−77 |
2 |
| GOST 6836−80 |
2 |
| GOST 8864−71 |
2 |
| GOST 18337−80 |
Chapeau |
| GOST 20288−74 |
2 |
| GOST 22519.0−77 |
1.1 |
5. Limitation of actions taken on the Protocol, the Interstate Council for standardization, Metrology and certification (ICS 2−93)
6. REPRINT (February 1998) with Amendments No. 1, 2, 3, approved in January 1983, March 1987-June 1996 (IUS 5−83, 6−87, 9−96)
This standard establishes the colorimetric method for the determination of silver (at a mass fraction of silver from 0.00003 up to 0,0003%) in thallium brands Tl00 and TL0 GOST 18337*.
______________
* On the territory of the Russian Federation GOST 18337−95. — Note the manufacturer’s database.
The method is based on the displacement of copper ions from diethyldithiocarbamate complex with silver ions. The decrease in the intensity of staining of copper diethyldithiocarbamate in carbon tetrachloride at pH 4 is proportional to the concentration of silver in an aqueous solution. Thallium, preventing the determination of silver, previously removed by extraction with ether from a solution containing bromatological acid.
The sensitivity of the method was 0.2 ág in a volume of 1 cm.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis and security requirements — according to GOST 22519.0.
(Changed edition, Rev. N 3).
2. APPARATUS, REAGENTS AND SOLUTIONS
Test-tubes of colourless glass with a flat bottom and ground stoppers with a diameter of 16 or 18 mm.
Separating funnel with a capacity of 100−150 cm.
Nitric acid according to GOST 4461 diluted 1:2 and a solution of 0.1 mol/DM.
Bromatologia acid according to GOST 2062, the solutions are 8 and 2 mol/DM.
Sulfuric acid according to GOST 4204, diluted 1:1.
Acetic acid according to GOST 61 and a solution of 0.2 mol/DM.
Ammonia water according to GOST 3760.
Bromine according to GOST 4109.
Sodium acetate according to GOST 199, a solution of 500 g/DM.
Carbon tetrachloride according to GOST 20288.
Ether ,
-dialogically (hloreksa).
Acetate buffer solution with pH 4,0; prepared as follows: into a measuring flask with a capacity of 1 DMmeasure 11.5 cm
of acetic acid, poured about 500 cm
of water, stirred, added 5.44 g sodium acetate, dilute to the mark with water and mix.
Diethyldithiocarbamate sodium GOST 8864, a solution of 10 g/DM.
The diethyldithiocarbamate copper, solution in carbon tetrachloride. Stock solution of copper diethyldithiocarbamate; prepared as follows: 40 mg of copper sulphate is dissolved in 40 cmof water, poured ammonia to pH 9, 4.5 cm
of a solution of sodium diethyldithiocarbamate transferred to a separatory funnel with a capacity of 150−200 cm
and extracted with carbon tetrachloride in portions of 20 cm
to obtain a colorless extract. The organic extract is washed in a separating funnel twice with water and transferred to a volumetric flask with a capacity of 500 cm
, is diluted to the mark with carbon tetrachloride and stirred.
A dilute solution of copper diethyldithiocarbamate; prepared as follows: 30 cmbasic solution is diluted with carbon tetrachloride in a volumetric flask with a capacity of 250 cm
. The optical density of a dilute solution of copper diethyldithiocarbamate against carbon tetrachloride net must be of 0.4−0.5.
Methyl orange, solution 10 g/DM.
Copper sulfate according to GOST 4165.
Silver GOST 6836*, mark SR 999.
______________
* On the territory of the Russian Federation GOST 6836−2002. — Note the manufacturer’s database.
Standard solutions of silver.
Solution A, prepared as follows: 0,100 g of silver dissolved in 10 cmof nitric acid, diluted 1:2, evaporated to obtain a moist salt, add 7 cm
of concentrated nitric acid, diluted with water, transferred to a volumetric flask with a capacity of 100 cm
, adjusted to the mark with water and mix.
1 cmof the solution contains 1 mg of silver.
Solution B is prepared as follows: 10 cmof a solution of A dilute solution of nitric acid 0.1 mol/l
in a volumetric flask with a capacity of 100 cm
.
1 cmof a solution contains 0.1 mg of silver.
Solution; prepared as follows: 1 cmof solution B dilute solution of nitric acid 0.1 mol/l
in a volumetric flask with a capacity of 100 cm
.
1 cmof the solution contains 1 µg of silver.
(Changed edition, Rev. N 2).
3. ANALYSIS
3.1. A portion of the thallium weighing 0,500 g (with mass fraction of thallium 99,98−99,99%), 3,000 g (with mass fraction of thallium 99,999-of 99.9995%) was placed in a flask with a capacity of 100 cmand dissolved by heating respectively at 4 and 8 cm
of nitric acid, diluted 1:1, and gently evaporated to dryness. Pour the 3 and 10 cm
solution bromatological acid 8 mol/DM
and evaporated up to wet salts. The residue is dissolved in 8 or 20 cm
solution bromatological acid 2 mol/DM
with the addition of 0.2 or 1 cm
of bromine, transferred to a separatory funnel. Flask in which to carry out the decomposition of the sample, then rinsed 5 cm
of the same acid and added to the solution in separating funnel. Poured into separating funnel 10 cm
or 30 cm
hloreksa and slowly shaken for 3 min. After separation the organic phase is drained through the valve, and to the aqueous solution in the funnel was added two drops of bromine, 10 cm
or 30 cm
hloreksa and the extraction repeated as above. The organic layer is drained through the valve and the extraction of thallium repeat for the third time.
After careful separation of the hloreksa the aqueous layer is drained through the throat in a beaker with a capacity of 50 cm, pour 1 cm
of sulfuric acid and drop by drop nitric acid to the bleaching solution, cooled, rinse walls of beaker with water and repeat the evaporation. To the residue poured 5cm
of water, heated to boiling and neutralized with a solution of sodium acetate in methyl orange, diluted to 40 cm
(label on the funnel) acetate buffer solution with pH 4, add 1 cm of
a dilute solution of copper diethyldithiocarbamate, and shake the funnel with a solution of 2 min. allow solution to settle and decanted layer of carbon tetrachloride in a test tube.
Colorimetric solution visually comparing the color of the sample solution with the color scale reference, which is prepared simultaneously with the sample.
(Changed edition, Rev.
N 1, 2, 3).
3.2. Preparation of the scale of standards
Poured in separating funnel and 30 cmof water, add 0; 1,0; 1,5; 2,0; 2,5; 3,0; 3,5; 4 cm
solution that fits 0; 1,0; 1,5; 2,0; 2,5; 3,0; 3,5; 4 mcg of silver solutions are neutralized with a solution of sodium acetate in methyl orange diluted to a volume of 40 cm
(the label on the funnel) acetate buffer solution with pH 4, add 1 cm of a
dilute solution of copper diethyldithiocarbamate, and shake the funnel with a solution of 2 min. allow solution to settle and decanted layer of carbon tetrachloride in a test tube. The reference scale is sustainable for 30 min.
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of silver () in percent is calculated by the formula
where is the mass of silver painted standard solution, which matched the color intensity of the sample, µg;
the weight of thallium,
(Changed edition, Rev. N 2).
4.2. The absolute values of the differences between the results of two parallel measurements (rate of convergence) and the results of the two tests (index of reproducibility) with confidence probability of 0.95 should not exceed the values permitted discrepancies listed in the table.
| Mass fraction of silver, % |
The permissible difference for parallel definitions % |
The permissible discrepancy between the results of the analysis % |
| From 0,00003 0,00005 up to incl. |
0,00002 |
0,00002 |
| SV. 0,00005 «0,00010 « |
0,00003 |
0,00004 |
| «0,00010» 0,00030 « |
0,00005 |
0,00007 |
(Changed edition, Rev. N 3).
