GOST 20580.7-80
GOST 20580.7−80 (ST SEV 912−78) Lead. Method for the determination of antimony (with Amendments No. 1, 2)
GOST 20580.7−80*
(CT CMEA 912−78)
Group B59
STATE STANDARD СОЮ3А SSR
LEAD
Method for the determination of antimony
Lead. Method for the determination of stibium
AXTU 1709***
________________
*** Revised edition, Edit. N 2.
Date of introduction 1980−12−01
Resolution of the USSR State Committee for standards, dated April 29, 1980, N 1976 the period of validity set with 01.12.80
Proven in 1983 by the Decree of Gosstandart from
________________
** Expiration removed by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (I & C N 11, 1995). — Note the manufacturer’s database.
REPLACE GOST 20580.7−75
* REPRINT December 1984, Change No. 1, approved in December 1983 (ICS 4−84)
The Change N 2, approved and put in force by the Decision of Gosstandart of the USSR from
Change No. 2 made by the manufacturer of the database in the text IUS N 11, 1990
This standard sets the photometric method for the determination of antimony from from 0.0002 to 0.25% lead (99,992−99,5%).
The method is based on the interaction of the ion [SbCI] — with crystal violet. The resulting water-insoluble complex is extracted well with toluene, staining it a blue-purple color. The optical density of the resulting solution measured at a wavelength of 610 nm.
Standard is fully consistent with CT CMEA 912−78.
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis and security requirements — according to GOST 20580.0−80.
(Changed edition, Rev. N 2).
1.2. (Deleted, Rev. N 2).
2. APPARATUS, REAGENTS AND SOLUTIONS
Spectrophotometer or photoelectrocolorimeter of any kind for measurements in the visible region of the spectrum.
Sulfuric acid according to GOST 4204−77.
Hydrochloric acid by the GOST 3118−77 and the solution (Hcl)=9 mol/DM.
Acetic acid GOST 61−75 and diluted 3:1.
Tartaric acid according to GOST 5817−77.
Antimony GOST 1089−82.
Hydrogen peroxide according to GOST 10929−76.
Iron chloride according to GOST 4147−74, a solution with a mass concentration of 10 g/DMsolution of hydrochloric acid concentration of 9 mol/DM.
Sodium atomistically according to GOST 4197−74, a solution with a mass concentration of 100 g/DM, freshly prepared.
Tin (II) chloride on the other 6−09−5384−88, a solution with a mass concentration of 100 g/lsolution of hydrochloric acid concentration of 9 mol/DM.
Urea according to GOST 6691−77, a solution with a mass concentration of 500 g/DM, freshly prepared.
Toluene according to GOST 5789−78.
Crystal violet, on the other 6−09−4119−75, a solution with a mass concentration of 2 g/DM.
Standard solutions of antimony.
Solution a: 0,100 g of metallic antimony powder was dissolved with heating in 20 cmof sulfuric acid, cooled, transferred into a measuring flask with volume capacity of 1000 cm, cooled, made up to the mark with hydrochloric acid concentration of 9 mol/land stirred.
1 cmof solution A contains 0.1 mg of antimony.
Solution B: 5 ml of solution A diluted solution of hydrochloric acid concentration of 9 mol/lin a volumetric flask with a capacity of 200 cm, made up to the mark with hydrochloric acid concentration of 9 mol/land stirred. 1 cmof a solution contains 0.0025 mg of antimony.
(Changed edition, Rev. N 1, 2).
3. ANALYSIS
3.1. Depending on the mass fraction of antimony take a sample of lead whose mass is listed in table.1.
Table 1
Mass fraction of SB, % |
The mass of charge, g |
The volume aliquote part of the solution, cm |
From 0,0002 to 0,001 |
1,000 |
The entire solution |
SV. Of 0.001 «to 0.005 |
2,000 |
10 |
«0,005» 0,01 |
1,000 |
10 |
«To 0.01» to 0.05 |
0,500 |
5 |
«0,05» 0,1 |
0,250 |
5 |
«Of 0.1» to 0.25 |
0,250 |
2 |
The charge is dissolved by heating in 15 cmof acetic acid (3:1) in the presence of 2 cmof hydrogen peroxide solution. Add 1 g of tartaric acid and the solution is evaporated to dry residue in a water bath. To the dry residue poured 10 cmof hydrochloric acid concentration of 9 mol/l, heated for 5 min in a water bath and cooled.
In the analysis of lead with a mass fraction of antimony from 0,0002 to 0,001% use entire solution. When the mass fraction of antimony in lead in excess of 0.001 to 0.25% solution transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with hydrochloric acid concentration of 9 mol/land stirred. For the determination of antimony taken aliquot part of the solution tab.1. If necessary, the volume was adjusted to 10 cm, priliva a hydrochloric acid solution with concentration 9 mol/DM. To the hydrochloric acid solution is added 1 cmof solution of ferric chloride, and then dropwise solution of tin chloride to a bleaching solution. Pour 2 cmof a solution of sodium attestatio and leave for 5 minutes, stirring occasionally. Pour 10 cmof distilled water, 1 cmof the urea solution and vigorously stirred for several minutes to destroy the excess oxidant. A decanting transfer the solution into the separatory funnel with a capacity of 100 cm. The precipitate of lead chloride is washed several times with water, adding the washings to the main decanting the solution. The total volume of the aqueous phase should be 50 cm.
To the solution in separating funnel pour 1 cmof the crystal violet solution, mix, add 20 cmof toluene and vigorously shaken for 2 min. In the presence of antimony organic extract is colored in blue-purple color. The aqueous layer is discarded and the toluene layer was filtered through a dry paper filter into the cuvette and measure the optical density of the solution in the region of wavelengths of 610−630 nm. Solution comparison is toluene. Simultaneously with the analysis carried out control experiments with all applicable in the analysis of the reagents and under the same conditions. The amount of antimony in kalorimetricheskim volume set calibration schedule.
(Changed edition, Rev. N 1, 2).
3.2. To build a calibration curve in five of the six cups with a capacity of 100 cmpoured from microburette respectively 1,0; 2,0; 3,0; 4,0 and 5,0 cmof a standard solution of antimony B, which corresponds to 2,5; 5,0; 7,5; 10,0 and 12,5 µg of antimony. The sixth glass is used for the reference experiment. The volume was adjusted to 10 cmsolution of hydrochloric acid concentration of 9 mol/DM, pour 1 cmof solution of ferric chloride and then do as stated in claim 3.1.
According to the obtained values of optical density of solutions and their corresponding weight fractions of antimony and build a calibration chart.
(Changed edition, Rev. N 1, 2).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of antimony in percent is calculated by the formula
,
where is the mass of antimony, was found in the calibration schedule g;
— volume of initial solution, cm;
— volume aliquote part of the solution, cm;
— its weight of lead,
4.2. Allowable absolute discrepancies in the results of parallel measurements and the results of the analysis shall not exceed the values given in table.2.
Table 2
Mass fraction of SB, % |
Permissible discrepancies parallel definitions % |
Permissible discrepancies in the results of the analysis % |
From to from 0.0002 to 0.0005 incl. |
0,0001 |
0,0001 |
SV. Of 0.0005 «0,0010 « |
0,0002 |
0,0003 |
«0,0010» 0,0030 « |
0,0004 |
0,0005 |
«0,0030» 0,0100 « |
0,0010 |
0,0013 |
«0,010» 0,030 « |
0,002 |
0,003 |
«0,030» 0,100 « |
0,005 |
0,006 |
«To 0.10» to 0.25 « |
0,01 |
0,02 |
(Changed edition, Rev. N 2).