GOST 1367.8-83
INTERSTATE STANDARD
ANTIMONY
Method for the determination of selenium
Antimony. Method for the determination of selenium
AXTU 1709
GOST
1367.8 -8 3
Resolution of the USSR State Committee on standards of 16 December 1983, No. 6013 date of introduction
installed 01.01.85
Limitation of actions taken by Protocol No. 4−93 of the Interstate Council for standardization,
Metrology and certification (ICS 4−94)
This standard specifies a method for the inversion perimentally polarography for
definition of selenium from 210−5 to 810−5% in the antimony brand Swoooop.
The method is based on the allocation of selenium in elemental form on the collector — sulphur and definition
the method of inversion perimentally polarography with accumulation of 0.4 mol/dm3 solution
sulfuric acid in the presence of ions of dichromate and copper (II).
(Changed edition, Rev. No. 1).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis and security requirements — according to GOST 1367.0−83.
2. APPARATUS, REAGENTS AND SOLUTIONS
Polarograph AC type PU-1.
Beakers, glass, laboratory for GOST 25336−82 with a capacity of 50, 100 cm3.
Volumetric flasks according to GOST 1770−74 with a capacity of 100 cm3.
Pipette with divisions for NTD with a capacity of 1, 2, 5 cm3.
The cylinders are graded according to GOST 1770−74 with a capacity of 50 cm3.
Nitric acid of high purity according to GOST 11125−84.
Hydrochloric acid of high purity according to GOST 14261−77 and 3 mol/dm3 and 6 mol/dm3 solutions.
A mixture of concentrated nitric and hydrochloric acids in a ratio of 3:1 (opposite the Royal
vodka).
Orthophosphoric acid according to GOST 6552−80.
Formic acid according to GOST 5848−73.
Bidistilled water (double-distilled water); prepared by distillation of distilled water in kvar
Zevon distillation apparatus.
Sulfuric acid of high purity according to GOST 14262−78 diluted 1:1 and 0.4 mol/dm3 solution.
Hydroxylamine hydrochloride according to GOST 5456−79, the solution with mass fraction 10% in 6 mol/dm3
a solution of hydrochloric acid and a solution with a mass fraction of 5% in 3 mol/dm3 solution of hydrochloric acid.
Chernovetskiy sodium (sodium thiosulfate) according to GOST 27068−86, a solution with a mass
a share of 30%.
Milk of sulphur: to 10 cm3 of solution with a mass fraction of 30% sodium chernovetskogo add
give 2 cm3 of concentrated sulfuric acid immediately before use.
Bromine according to GOST 4109−79.
Official edition Reprinting is prohibited
Edition with amendments No. 1, approved in March 1989 (IUS 6−89).
54
frame construction
GOST 1 367.8−83 C. 2
Potassium dichromate according to GOST 4220−75, a solution with a mass fraction of 5%.
Copper sulfate according to GOST 4165−78, a solution containing 500 µg 1 cm3 of copper.
Selenium on the other 6−09−5358−87.
The standard solutions of selenium.
Solution a: 0.1 g of metallic selenium, is placed in a beaker with a capacity of 100 cm3 and dissolved
when heated in 10 cm3 of reverse Aqua Regia. Then add 5 cm3 of concentrated sulfuric
acid, is evaporated prior to the allocation of steams of sulfuric acid, cooled, poured pedistal
late, boil and cool again. The resulting solution was transferred to volumetric flask with a capacity of
100 cm3, adjusted with double-distilled water to the mark and mix.
1 cm3 of the solution contains 1 mg selenium.
Solution B: 1 cm3 of solution And poured into a measuring flask with a capacity of 100 cm3, poured
0.4 mol/dm3 sulfuric acid solution to the mark and mix; prepared on the day of use.
1 cm3 of solution B contains 0.01 mg of selenium.
(Changed edition, Rev. No. 1).
3. ANALYSIS
3.1. A portion of the antimony brand Swoooop a mass of 1 g was placed in a beaker with a capacity of 100 cm3,
pour 10 cm3 of reverse Aqua Regia, the solution evaporated to almost dryness on a boiling water
bath and spend denitration residue of formic acid. The excess formic acid
removed by evaporation of water. Traces of formic acid do not interfere further.
NIJ. The precipitate is then dissolved in 20 cm3 of a 10% solution of hydroxylamine in 6 mol/dm3 solution
hydrochloric acid, the solution transferred into a test tube and precipitated sulfur. To do this, the test tube with solution
placed in a boiling water bath, add a pipette of 0.5 cm3 of milk and sulphur soak
the solution is evaporated on a water bath for 3 h. During this time, three times add 0.3 cm3 of sulfur milk
after 30 min, 1 HR and end of the experience. The next day the separated precipitate is sulfur-containing
selenium, filtered through a filter with a white ribbon and washed first 7 times 5%
a solution of hydroxylamine hydrochloride in 3 mol/dm3 solution of hydrochloric acid, and then 5 times
the double-distilled water. The precipitate is washed with a jet of double-distilled water in a beaker with a capacity of 50 cm3, add
1 cm3 of nitric acid, 1 cm3 of sulfuric acid (1:1) and 0.5 cm3 of bromine and leave the glass under
watch glass for 30 min. the solution was Then heated in a water bath until distillation of the excess bromine
and removed on the tile before the appearance of sulphuric acid fumes. The contents of the glass
add 5 cm3 of double-distilled water, 0,2 cm3 of solution of potassium dichromate and 0.2 cm3 of solution
sulphate of copper. The solution was adjusted with double-distilled water to a volume of 30 cm3 in a measuring cylinder with
stopper and mix.
3.2. Polarographic solution in the cell with a remote electrode compared mercuriality
tion on the stationary mercury electrode. Mercury in the bottom of the anode compartment is filled with a mixture of
sulfuric acid, phosphoric acid and double-distilled water in the ratio 1:1:2. Droplet size
corresponds to 20 divisions of the clock indicator. The accumulation time 1−3 min at a potential of
the accumulation of minus 0.6 V. At check polarogram use of cathodic voltage scan
tion. The peak potential of -0.8 V. Polarogram of each solution is removed three to four times
in the interval of potentials from minus 0.6 V to minus 1.0 V. the peak Height is measured vertically
drawn through the top of the peak to the intersection with a tangent connecting the bases of the branches
peak. Concentration of selenium in solution was determined by method of additions. With each series of samples
conduct three follow-up experience.
(Changed edition, Rev. No. 1).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of selenium (X) in percent is calculated by the formula
t \ '
t (N2 — #,) IQ"4 ,
where MX is the mass of selenium in Supplement mcg;
HX — arithmetic average peak height of the sample solution minus the average value
the peak height of control experiments, mm;
55
C. 3 367.8 1 GOST-83
H2 — the mean arithmetic height of the peak of the sample solution with the additive minus the average
the values of the peak height of control experiments, mm (difference between H2 and H1 should be
less I, and no more GIA,);
t — the weight of antimony,
4.2. The difference between the two results of parallel measurements and the difference between two analysis results
at confidence probability P = 0.95 does not exceed the allowable absolute popular
Denia convergence and reproducibility given in the table.
Absolute peppermint allowable difference, %
M associe fraction of selenium, %
the convergence of reproducibility
From 0,000020 to 0,00004 incl.
SV. 0,00004 «0,00008 «
0,000015
0,00002
0,00002
0,00003
(Changed edition, Rev. No. 1)
