GOST 12645.5-77
GOST 12645.5−77 indium. Methods for determination of arsenic (with Amendments No. 1, 2, 3)
GOST 12645.5−77
Group B59
STATE STANDARD OF THE USSR
INDIUM
Methods for determination of arsenic
Indium. Methods for determination of arsenic
AXTU 1709
Date of introduction 1978−07−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
A. P. Sychev, L. K. Larina (supervisor), M. G. Saun (supervisor), V. N. Makarceva, N. With. References: E. V. Lisitsyn, N. 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
The adoption voted:
| The name of the state |
The name of the national authority for standardization |
| The Republic Of Azerbaijan |
Azgosstandart |
| 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 |
| Turkmenistan |
The main state inspection of Turkmenistan |
| The Republic Of Uzbekistan |
Standards |
| Ukraine |
Gosstandart Of Ukraine |
3. REPLACE GOST 12645−67 in part of sec. 2
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
The number of the paragraph, subparagraph |
| GOST 1973−77 |
2.2, 3.2 |
| GOST 3118−77 |
2.2, 3.2 |
| GOST 3765−78 |
2.2, 3.2 |
| GOST 4204−77 |
2.2, 3.2 |
| GOST 4232−74 |
2.2, 3.2 |
| GOST 4328−77 |
2.2, 3.2 |
| GOST 4461−77 |
3.2 |
| GOST 5830−79 |
2.2, 3.2 |
| GOST 5841−74 |
2.2, 3.2 |
| GOST 6709−72 |
2.2, 3.2 |
| GOST 11125−84 |
2.2 |
| GOST 12645.0−83 |
1.1 |
| GOST 18300−87 |
2.2 |
| GOST 19908−90 |
2.2 |
| GOST 20490−75 |
3.2 |
| GOST 20288−74 |
2.2, 3.2 |
| GOST 22306−77 |
1.1 |
5. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
6. REPRINT (January 1998) with Amendments No. 1, 2, 3, approved in February 1983, December 1987-June 1996 (IUS 5−83, 3−88, 9−96)
This standard specifies a visual colorimetric method for the determination of arsenic in India, when the mass fraction of arsenic from 3·10to 1·10
% and photocolorimetric method for the determination of arsenic at a mass concentration of arsenic from 1·10
to 5·10
%.
(Changed edition, Rev. N 1, 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis and security requirements — according to GOST and GOST 12645.0 22306.
(Changed edition, Rev. N 2).
2. VISUAL COLORIMETRIC METHOD FOR THE DETERMINATION OF ARSENIC CONTENT
2.1. The essence of the method
The method is based on formation of yellow arsenic-molybdenum complex followed by reduction of its sulfate with hydrazine in acidic solution to molybdenum blue, the intensity of the color in which the organic layer is compared with the scale of standards.
2.2. Apparatus, reagents and solutions
Quartz ware according to GOST 19908.
Cylinders for photometry with a glass stopper with a height of 18 cm and a diameter of 1 cm.
Nitric acid according to GOST 11125.
Sulfuric acid according to GOST 4204, diluted 1:1 and the solution (H
SO
)=3 mol/DM
.
Hydrochloric acid according to GOST 3118, density of 1.19 g/cm(check the hydrometer is optional), purified from arsenic in the following manner: in 500 cm
of hydrochloric acid dissolve 10 g of potassium iodide according to GOST 4232. The solution was transferred to a separatory funnel with a capacity of 1 DM
, poured 25 cm
of carbon tetrachloride and shaken for 2 min, then allowed to settle and decanted the organic layer. The aqueous layer again extracted with 25 cm
of carbon tetrachloride. The organic layer discarded. Hydrochloric acid solution
(HCl)=9 mol/DM
; prepared from arsenic hydrochloric acid, diluted with water 3:1.
Hydrazine sulfate according to GOST 5841, a solution containing 1.5 g/l, and diluted 1:19 (5 cm
of a solution containing 1.5 g/l
of hydrazine, diluted to 100 cm
water). Ammonium molybdate according to GOST 3765, a solution containing 10 g/l
in sulfuric acid
(H
SO
)=3 mol/DM
.
Carbon tetrachloride according to GOST 20288.
Isoamyl alcohol according to GOST 5830.
Arsenious anhydride according to GOST 1973.
Standard solutions of arsenic.
Solution a: 0,132 g of arsenious anhydride is dissolved by heating in 5−10 cmof sodium hydroxide solution, transferred to a volumetric flask with a capacity of 1 DM
, neutralized to phenolphthalein with sulfuric acid solution
(H
SO
)=3 mol/DM
, dilute to the mark with water and mix.
1 cmof solution A contains 0.1 mg of arsenic.
Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm
and adjusted to the mark with water.
1 cmof a solution containing 10 µg of arsenic.
Solution: 1 cmof solution A is placed in a volumetric flask with a capacity of 100 cm
and adjusted to the mark with water.
1 cmof the solution contains 1 ág of arsenic.
Distilled water according to GOST 6709 double-distilled in quartz apparatus.
Sodium hydroxide according to GOST 4328, a solution containing 100 g/DM.
Phenolphthalein (indicator) solution in alcohol containing 1 g/DM.
Ethyl alcohol according to GOST 18300.
(Changed edition, Rev. N 2, 3).
2.3. Analysis
2.3.1. The weight India weight 0,500−1,000 g was placed in a quartz flask with a capacity of 100 cm, pour 5 cm
of sulphuric acid diluted 1:1, and dissolve the sample on a hot plate covered with a quartz cover. The solution was evaporated to 2−2,5 cm
, cool, add 2.4 cm
of water, again cooled and dissolve the salt in 7.8 cm
purified hydrochloric acid with stirring and cooling.
After cooling, transfer the solution into a separating funnel with a capacity of 75−100 cm, the glass is washed with 2 cm
of hydrochloric acid solution
(HCl)=9 mol/DM
. Then perform the extraction of arsenic 15 cm
of carbon tetrachloride for 2 min. Supernatant organic layer drained into another separatory funnel. Extraction of arsenic repeat and attach the organic layer to the first. The combined extracts are washed with 10 cm
of hydrochloric acid solution
(HCl)=9 mol/l
, shaking for 15−20 s.
The washed extract was drained into another separatory funnel where it is shaken for 2 min with 10 cmof water. In this case the arsenic passes into the aqueous layer. The aqueous layer is poured into a quartz Cup with a capacity of 30−50 cm
, add 3 cm
of nitric acid and evaporate on a water bath to dryness.
The dry residue is dissolved in 2 cmof water in low heated in a water bath, the solution was transferred to a cylinder for colorimetrically a height of 18 cm and a diameter of 1 cm with a glass stopper. The Cup is washed with water. The total volume of the solution in the cylinder should be 3 cm
.
Then poured into the cylinder 0.3 cmof a solution of ammonium molybdate, 0.15 cm
of a solution of hydrazine sulfate (1.5 g/DM
) and mixed. The cylinder with the test solution is immersed in a glass of boiling water and allowed to stand 5 min. from the moment of boiling water. Then the cylinder is rapidly cooled, added 0.5 cm
isoamyl alcohol, shaken for 10 s and compare (side) coloring the supernatant alcohol layer with a scale comparison. At the same time under the same conditions conduct control experience with reagents for inclusion in the analysis result of the relevant amendment.
The amount of arsenic in kalorimetricheskim solution set by comparing with a scale of comparison.
(Changed edition, Rev. N 2, 3).
2.3.2. Preparation of the scale comparison
Seven cylinders for colorimetrically a height of 18 cm and a diameter of 1 cm was placed 0; 0,1; 0,2; 0,4; 0,6; 0,8 and 1 cmstandard solution, which corresponds to 0; 0,1; 0,2; 0,4; 0,6; 0,8 and 1 µg of arsenic, the volume was adjusted with water to 3 cm
and mixed. Go 0.3 cm
of a solution of ammonium molybdate, 0.15 cm
of a solution of hydrazine sulfate and further analysis are as indicated in claim
(Changed edition, Rev. N 2).
2.4. Processing of the results
2.4.1. Mass fraction of arsenic () in percent is calculated by the formula
where the amount of arsenic in sample, µg;
— amount of arsenic in solution in the reference experiment, µg;
— the weight of the portion India,
2.4.2. For the results analysis be the arithmetic mean of results of three parallel measurements.
The difference between the largest and smallest of the three results of parallel measurements with a confidence probability of 0.95 does not exceed the value of permissible differences
of the three results of parallel measurements calculated by the formulae:
to 5·10
%;
to 1·10
%,
where is the arithmetic mean of results of three parallel measurements.
The difference between the smaller and larger of the two results of the analysis of the same samples with a confidence level of 0.95 does not exceed the value of permissible differences
of the two analysis results calculated by the formulae:
to 5·10
%;
to 1·10
%,
where — the average of the two comparable test results.
(Changed edition, Rev. N 2).
3. PHOTOCOLORIMETRIC METHOD FOR THE DETERMINATION OF ARSENIC CONTENT
3.1. The essence of the method
The method is based on formation of yellow arsenic-molybdenum complex followed by reduction of its sulfate with hydrazine in acidic solution to molybdenum blue and the measurement of the optical density of the colored complex in the region of wavelengths of 660−680 nm.
3.2. Apparatus, reagents and solutions
Photoelectrocolorimeter.
Nitric acid according to GOST 4461.
Sulfuric acid according to GOST 4204, diluted 1:1 and the solution (H
SO
)=3 mol/DM
.
Titanium trichloride.
Hydrochloric acid according to GOST 3118, density of 1.19 g/cmand the solution
(HCl)=9 mol/DM
.
Carbon tetrachloride according to GOST 20288.
Potassium permanganate according to GOST 20490, a solution of 1 g/DM.
Ammonium molybdate according to GOST 3765, a solution containing 10 g/lin sulfuric acid
(H
SO
)=3 mol/DM
.
Hydrazine sulfate according to GOST 5841, a solution containing 1.5 g/l, and diluted 1:19 (5 cm
of a solution containing 1.5 g/l
of hydrazine, diluted to 100 cm
water).
Potassium iodide according to GOST 4232.
Standard solutions of arsenic.
Solution a: 0,132 g of arsenious anhydride is dissolved by heating in 5−10 cmof sodium hydroxide solution, transferred to a volumetric flask with a capacity of 1 DM
, neutralized to phenolphthalein with sulfuric acid solution
(H
SO
)=3 mol/DM
, dilute to the mark with water and mix.
1 cmof solution A contains 0.1 mg of arsenic.
Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm
and adjusted to the mark with water.
1 cmof a solution containing 10 µg of arsenic.
Distilled water according to GOST 6709, double-distilled in quartz apparatus.
Arsenious anhydride according to GOST 1973.
Sodium hydroxide according to GOST 4328, a solution containing 100 g/DM.
Phenolphthalein (indicator) solution in alcohol containing 1 g/DM.
(Izmenen
the second edition, Rev. N 2).
3.3. Analysis
3.3.1. The weight India weight 0,200−2,000 g was placed in a flask with a capacity of 100 cm, is dissolved in 10 cm
of nitric acid, add 5 cm
of sulphuric acid diluted 1:1, and evaporated until the appearance of a dense vapour. After cooling, the flask wall is washed with a small amount of water and again evaporated to the appearance of sulphuric acid fumes. The cooled residue is dissolved in 15 cm
of water is added to it dropwise a solution of trichloride titanium to lilac color of the solution in excess of 0.2 cm
. The test solution was placed in a separating funnel with a capacity of 150 cm
, add to it 45 cm
purified hydrochloric acid density of 1.19 g/cm
, with 20 cm
of carbon tetrachloride and perform the extraction of arsenic for 2 min. Then the extract is allowed to settle, and then drained the organic layer into another separatory funnel. The extraction is repeated. The combined extracts are washed with 10 cm
of hydrochloric acid solution
(HCl)=9 mol/DM
, shaken for 15−20 s. the Washed extract was drained into another separatory funnel where it is shaken for 2 min with 10 cm
of water. In this case the arsenic passes into the aqueous layer. Extraction of arsenic of 10 cm
water repeat. The combined aqueous layers are decanted into a conical flask with a capacity of 100 cm
, are added dropwise a solution of potassium permanganate until a stable pink color of the solution. After 3 min add 1 cm
of molybdenic acid ammonium solution and heated to boiling. Then added dropwise a solution of hydrazine (1.5 g/DM
) until discoloration of potassium permanganate, injected 2 cm
diluted 1:19 solution of hydrazine and boil for 2−3 min. the Solution was cooled and transferred to volumetric flask with a capacity of 25 cm
, adjusted to the mark with water and mix.
Measure the optical density of the solution on the photoelectrocolorimeter, applying the filter to the transmission 660−680 nm in a cuvette with a thickness of the light absorbing layer was 50 mm.
Solution comparison in the measurement of optical density is water.
At the same time under the same conditions conduct control experience with reagents for inclusion in the analysis result of the relevant amendment.
The amount of arsenic in kalorimetricheskim volume set calibration schedule.
(Changed edition, Rev. N 2, 3).
3.3.2. Construction of calibration curve
In a conical flask with a capacity of 25 cmis placed 0; 0,25; 0,5; 1,0; 1,5 and 2,0 cm
standard solution B, which corresponds to 0; 2,5; 5; 10; 15 and 20 ág of arsenic, poured, up to 20 cm
of water and dropwise a solution of potassium permanganate until a stable pink color of the solution. After 3 min add 1 cm
of a solution of molybdate of ammonium and further analysis are as indicated in claim
On the found values of optical density and corresponding arsenic concentrations to build calibration curve.
3.4. Processing of the results
3.4.1. Mass fraction of arsenic () in percent is calculated by the formula
where - quantity of arsenic was found in the calibration schedule of ICG, net of the amount of arsenic in the reference experiment;
- the weight of the portion India,
3.4.2. For the results analysis be the arithmetic mean of results of three parallel measurements.
The difference between the largest and smallest of the three results of parallel measurements with a confidence probability of 0.95 does not exceed the value of permissible differences
of the three results of parallel measurements calculated by the formula
where is the arithmetic mean of the three results of parallel measurements.
The difference between the smaller and larger of the two results of the analysis of the same samples with a confidence level of 0.95 does not exceed the values allowed by rashidinia
two analysis results calculated by the formula
where — the average of the two matched analyses.
(Changed edition, Rev. N 2, 3).
