GOST 1367.2-83
Approved
By the decree of Gosstandart of the USSR
December 16, 1983 N 6012
STATE STANDARD OF THE USSR
ANTIMONY
METHODS OF IRON DETERMINATION
Antimony. Methods for the determination of iron
GOST 1367.2−83
Group B59
AXTU 1709
Replace GOST 1367.2−76
The validity of
from January 1, 1985
before January 1, 1990
This standard sets the photometric and atomic absorption methods for determination of iron from 0.008 to 0.15% antimony grades Su00, su0, SS1 and SS2.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis and security requirements — according to GOST 1367.0−83.
2. PHOTOMETRIC METHOD
The method is based on formation of the orange-red complex compound o-fenantrolina with ions of bivalent iron at pH 2 — 9 and fotomaterialy of the resulting complex at a wavelength of 510 nm.
2.1. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter of any kind for measurements in the visible region of the spectrum.
Beakers according to GOST 1770−74 with a capacity of 50, 100 and 250 cm3.
Volumetric flasks according to GOST 1770−74 with a capacity of 100 cm3 and 1 dm3.
Flasks laboratory glass according to GOST 25336−82 with a capacity of 100 cm3.
Beakers, glass, laboratory for GOST 25336−82 with a capacity of 100 cm3.
Pipette with divisions according to GOST 20292−74 with a capacity of 1, 2, and 10 cm3.
Hydrochloric acid by the GOST 3118−77.
Tartaric acid according to GOST 5817−77, a solution with a mass fraction of 25%.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Hydrogen peroxide according to GOST 10929−76.
Hydroxylamine hydrochloride according to GOST 5456−79, a solution with a mass fraction of 10%, freshly prepared.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Sodium acetate according to GOST 199−78, a solution with a mass fraction of 50%.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
On-fenantrolin hydrochloric acid, a solution with a mass fraction of 0.5%, freshly prepared.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Iron metal, reduced hydrogen, GOST 9849−86.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Solution iron standard: a sample of iron, the reduced hydrogen, with a mass of 0.1 g was placed in a beaker with a capacity of 100 cm3, poured 10 cm3 of hydrochloric acid and dissolve by heating with the addition of hydrogen peroxide. Once dissolved, pour 20 — 30 cm3 of water, boiled, cooled, poured into a volumetric flask with a capacity of 1 dm3, made up to the mark with water and mix.
1 cm3 of solution contains 0.1 mg of iron.
2.2. Analysis
2.2.1. A portion of the antimony in weight 0.5 g brands Su00, su0 or a mass of 0.1 g brands SS1, SS2 are placed in a glass or wide-mouthed conical flask with a capacity of 100 cm3, poured 5 cm3 of hydrochloric acid and dissolved by heating and stirring with the dropwise addition of hydrogen peroxide. After dissolution of the sample contents of the flasks is evaporated to 1 — 2 cm3, poured 5 cm3 of tartaric acid, 10 cm3 of water, cover with a watch glass and boil for 1 min. Then add 10 cm3 of the hydrochloride of hydroxylamine, the solution is neutralized with sodium acetate to pH 3 to 3.5 (this takes approximately 7 — 8 cm3 of a solution of sodium acetate). Pour 2 cm3 of excess sodium acetate, 10 — 20 cm3 water, 10 cm3 o-fenantrolina and pour the solution into volumetric flask with a capacity of 100 cm3, adding to the mark with water. After each addition of the reagent the solution was stirred.
After 30 min, measure the optical density of the solution at a wavelength of 510 nm in a cuvette with a length of 20 mm. Solution comparison the solution serves as the reference experiment. Weight of iron in the sample solution set the calibrationschedule.
2.2.2. The construction of the calibrationgraph
In eight of the nine volumetric flasks with a capacity of 100 cm3, poured 0,2; 0,4; 0,6; 0,8; 1,0; 1,2; 1,4; 1,6 cm3 of a standard solution, which corresponds to 0,02; 0,04; 0,06; 0,08; 0,10; 0,12; 0,14; 0,16 mg of iron. Ninth, the flask is used for the reference experiment. The walls of the flasks should be rinsed with approximately 10 cm3 of water, pour the 5 cm3 of tartaric acid, 10 cm3 of the hydrochloride hydroxylamine and then act as described in section
On the found values of optical densities and corresponding them with weight fractions of iron to build the calibrationgraph.
2.3. Processing of the results
2.3.1. Mass fraction of iron (X) in percent is calculated by the formula
,
where is the mass of iron in a solution of the sample, was found in the calibration graphics mg;
— the weight of antimony, g.
2.3.2. The difference between the two results of parallel measurements and the difference of two analysis results with a confidence probability P = 0.95 does not exceed the allowable absolute differences of precision and reproducibilityare shown in table. 1.
Table 1
────────────────────────────┬─────────────────────────────────────
Mass fraction of iron, % │allowable Absolute differences, %
├───────────────────┬─────────────────
│ convergence │reproducibility
────────────────────────────┼───────────────────┼─────────────────
From 0,008 to 0,010 incl. │0,002 │0,003
SV. 0,010 «0,020» │0,003 │0.004 s
«0,020» 0,040 «│0,005 │0,006
«0,040» 0,100 «│0,010 │0,012
«0,10» 0,15 «│0,02 │0,03
(2.3.2 as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
2.3.3. The method is applied when differences in the assessment of the quality of the antimony.
3. ATOMIC ABSORPTION METHOD
The method is based on measuring atomic absorption of iron, the introduction of the sample solution and solutions compare to the flames of propane-butane-air or acetylene-air.
3.1. Apparatus, reagents and solutions
Spectrophotometer atomic absorption Perkin-Elmer 503 or equivalent atomic absorption spectrophotometer.
Gas propane-butane according to GOST 20448−80.
Beakers, glass, laboratory for GOST 25336−82 with a capacity of 50 and 100 cm3.
Flasks laboratory glass according to GOST 25336−82 with a capacity of 100 cm3.
Volumetric flasks according to GOST 1770−74 with a capacity of 25, 50 cm3 and 1 dm3.
Pipette with divisions according to GOST 20292−74 with a capacity of 1, 2, and 5 cm3.
Hydrochloric acid by the GOST 3118−77.
Tartaric acid according to GOST 5817−77, a solution with a mass fraction of 25%.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Hydrogen peroxide according to GOST 10929−76, a solution with a mass fraction of 30%.
(as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
Iron metal, reduced hydrogen, GOST 9849−74.
Solution iron standard: a sample of iron, the reduced hydrogen, with a mass of 0.1 g was placed in a beaker with a capacity of 100 cm3, poured 10 cm3 of hydrochloric acid and dissolve by heating with the addition of hydrogen peroxide. Once dissolved, pour 20 — 30 cm3 of water, boiled, cooled, poured into a volumetric flask with a capacity of 1 dm3, made up to the mark with water and mix.
1 cm3 of solution contains 0.1 mg of iron.
3.2. Analysis
3.2.1. A portion of the antimony with a mass of 0.25 g brands Su00, su0 or a mass of 0.1 g brands SS1, SS2 are placed in a beaker with a capacity of 50 — 100 cm3, poured 5 cm3 of hydrochloric acid dropwise while stirring, add the hydrogen peroxide. After dissolution of the sample poured 5 cm3 of tartaric acid, 5 — 10 cm3 of water and heated to boiling. The solution was boiled, cooled, poured into a volumetric flask with a capacity of 25 cm3, made up to the mark with water and mix.
The resulting solution of antimony sprayed into the flame and measure the absorbance at a wavelength of 248.3 nm.
At the same time carried out two test experience with all the applied reagents. The average value of the absorption solution in the reference experiment is subtracted from the value of absorbance of sample solution.
Weight of iron in solution of the sample determined by the calibrationschedule.
3.2.2. The construction of the calibrationgraph
In a volumetric flask with a capacity of 25 cm3 are successively poured 0,2; 0,4; 0,6; 0,8; 1,0; 1,5 cm3 of a standard solution of iron, which corresponds to 0,02; 0,04; 0,06; 0,08; 0,10; 0,15 mg of iron. The seventh flask is used for the reference experiment. All flasks are poured 5 cm3 of hydrochloric acid, 5 cm3 of tartaric acid, transferred to a volumetric flask with a capacity of 25 cm3, made up to the mark with water and mix.
The concentration of iron in solution, respectively equal 0,8; 1,6; 2,4; 3,2; 4,0; 6,0 mg/dm3.
The solutions comparison is sprayed into the flame in order of increasing iron content. Measurement of analytical signal, And for each solution and sample solution is carried out three times and calculate the average arithmetical values for each solution. According to the average values for comparison of solutions to build the calibration graph. The abscissa shows the concentration of iron lay, and on the y — axis the absorbance.
3.3. Processing of the results
3.3.1. Mass fraction of iron (X) in percent is calculated by the formula
,
where with — the concentration of iron in solution of the sample, was found in the calibration graph and the average value obtained for the sample solution, mg/dm3;
V — the solution volume of the sample, cm3;
m — the weight of antimony, g.
3.3.2. The difference between the two results of parallel measurements and the difference of two analysis results with a confidence probability P = 0.95 does not exceed the allowable absolute differences of precision and reproducibilityare shown in table. 2.
Table 2
────────────────────────────┬─────────────────────────────────────
Mass fraction of iron, % │allowable Absolute differences, %
├───────────────────┬─────────────────
│ convergence │reproducibility
────────────────────────────┼───────────────────┼─────────────────
From 0,008 to 0,010 incl. │0,003 │0.004 s
SV. 0,010 «0,020» │0,004 │0,006
«0,020» 0,040 «│0,006 │0,007
«0,04» 0,10 «│0,01 │0,02
«0,10» 0,15 «│0,02 │0,03
(paragraph 3.3.2 as amended by Change No. 1, approved. By the decree of Gosstandart of the USSR from
