GOST 20580.2-80
GOST 20580.2−80 (ST SEV 907−78) Lead. Methods for determination of copper (with Amendments No. 1, 2)
GOST 20580.2−80*
(CT CMEA 907−78)
Group B59
STATE STANDARD OF THE USSR
LEAD
Methods for determination of copper
Lead. Methods for the determination of copper
AXTU 1709**
________________
** Changed revision, Rev. 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 20580.2−75
* REPRINT December 1984, Change No. 1, approved in December 1983 (ICS 4−84)
The Change N 2 approved and put into effect by the Decree 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 establishes photometric methods for determination of copper from of 0.0002 to 0.15% in the lead (99,992−99,5%).
The standard fully complies ST SEV 907−78.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis and security requirements — according to GOST 20580.0−80.
(Changed edition, Rev. N 2).
1.2. (Deleted, Rev. N 2).
2. PHOTOMETRIC METHOD WITH CUPRIZONE
The method is based on the formation at pH 9 are blue copper compounds with cuprizone and measuring the optical density of the resulting complex at a wavelength of 590 nm.
A lead mask with citric acid.
2.1. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter of any kind for measurements in the visible region of the spectrum.
Nitric acid GOST 4461−77 diluted 1:1.
Citric acid according to GOST 3652−69, a solution with a mass concentration of 200 g/DM.
Ammonia water according to GOST 3760−79.
Cuprizone on the other 6−09−14−1380−77, a solution with a mass concentration of 5 g/DM.
Boric acid according to GOST 9656−75.
Sodium hydroxide according to GOST 4328−77, solutions (NaOH)=1 mol/DMand (NaOH)=0.1 mol/DM.
Borate buffer solution with a pH of 9.3±0,2: 12,367 g of boric acid are dissolved in 100 cmof solution of sodium hydroxide of concentration 0.1 mol/DMand dilute with water to 1000 cm. Then 10.2 cmof sodium hydroxide solution of concentration 0.1 mol/DMdilute the resulting solution to 100 cm.
Ethyl alcohol GOST 18300−87.
Copper GOST 859−78*.
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* On the territory of the Russian Federation GOST 859−2001, here and hereafter. — Note the manufacturer’s database.
Standard solutions of copper.
Solution a: 0,100 g of electrolytic copper is dissolved in 10 cmof nitric acid and at weak boiling removes oxides of nitrogen. After cooling, the solution is transferred into a measuring flask with volume capacity of 1000 cm, is diluted to the mark with water and mix.
1 cmof solution A contains 0.1 mg of copper.
Solution B: 5 cmmortar And transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.
1 cmof the solution contains 0.001 mg of copper.
Water bidistilled.
(Changed edition, Rev. N 1, 2).
2.2. Analysis
2.2.1. Depending on the expected mass fraction of copper take a sample of lead whose mass is listed in table.1.
Table 1
Mass fraction of copper, % |
The weight of the portion of the lead, g |
The volume aliquote part of the solution, cm |
From to from 0.0002 to 0.0005 |
0,500 |
The entire volume |
SV. Of 0.0005 «to 0.001 |
1,000 |
20 |
«Of 0.001» to 0.005 |
0,500 |
10 |
«0,005» 0,01 |
0,500 |
5 |
«To 0.01» to 0.05 |
0,250 |
3 |
«To 0.05» to 0.15 |
0,200 |
2 |
Table 1. (Changed edition, Rev. N 2).
The sample is dissolved in 7−8 cmof nitric acid solution. After complete dissolution the solution was boiled to remove oxides of nitrogen. When the mass fraction of copper is higher 0,0005% solution transferred to a volumetric flask with a capacity of 50 cm, is diluted to the mark with water and mix.
The whole solution or its aliquot part of the selected tab.1, containing from 1 to 8 micrograms of copper, is evaporated to a volume of 1−2 cm. Add 8 cmof a solution of citric acid and slightly basified with ammonia solution to pH 9,0±0,2 on the indicator paper. After this, the solution was transferred to volumetric flask with a capacity of 25 cm, washing the Cup 5 cmbuffer solution and 3−4 cmof water. Pour 4 cmof solution cuprizone, made up to the mark with water, mix and after 20 min, measure the optical density of the solution at a wavelength of 590 nm.
Solution comparison is the solution of the reference experiment. The amount of copper in kalorimetricheskim volume set calibration curve
.
2.2.2. To build a calibration curve in eight of the nine cups with a capacity of 50 cmmake 1, 2, 3, 4, 5, 6, 7 and 8 cmstandard solution B, which corresponds to 1, 2, 3, 4, 5, 6, 7 and 8 µg of copper. The solution was evaporated to a volume of 1−2 cm. The ninth glass is used for the reference experiment. All nine of cups poured in 8 cmof a solution of citric acid and then act as mentioned in paragraph
According to the obtained values of optical density of solutions and their corresponding grades of copper to build the calibration graph.
2.2. (Changed edition, Rev. N 2).
3. PHOTOMETRIC METHOD WITH DIETHYLDITHIOCARBAMATE LEAD
The method is based on the ability of copper ion to replace lead in his diethyldithiocarbamate complex dissolved in chloroform. Yellow color formed of copper diethyldithiocarbamate photometric in the region of wavelengths 430−455 nm.
3.1. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter of any kind for measurements in the visible region of the spectrum.
Nitric acid GOST 4461−77 and diluted 1:1 and 1:2.
Sodium hydroxide according to GOST 4328−77, a solution with a mass concentration of 100 g/DM.
Potassium-sodium vinocity according to GOST 5845−79 or tartaric acid according to GOST 5817−77, solutions with the mass concentration of 400 g/DMand 100 g/DM.
Phenolphthalein on the other 6−09−5360−87, a solution with a mass concentration of 10 g/DMin alcohol.
Sodium sulphate anhydrous according to GOST 4166−76.
Water bidistilled.
Ammonia water according to GOST 3760−79.
Chloroform or carbon tetrachloride according to GOST 20288−74.
Ethyl alcohol GOST 18300−87.
Diethyldithiocarbamate sodium GOST 8864−71.
Lead acetate according to GOST 1027−67.
A solution of lead diethyldithiocarbamate in chloroform or carbon tetrachloride: 0.1 g of lead acetate dissolved in 20 cmof water is added 10 cmof the solution minocycli potassium-sodium salt with the mass concentration of 400 g/DMsolution of sodium hydroxide to alkaline reaction and the disappearance of turbidity. The solution was transferred to a separatory funnel with a capacity of 500 cm, add 0.1 g of sodium diethyldithiocarbamate dissolved in 20 cmof water, pour 250 cmof chloroform or carbon tetrachloride and extracted to completely dissolve the white precipitate of lead diethyldithiocarbamate. After separation of the aqueous phase of the extract is shaken with double-distilled water and filtered through a dry filter paper, collecting the filtrate in a dry volumetric flask with a capacity of 500 cm, and then topped to the mark with chloroform or carbon tetrachloride. If the layer of chloroform or carbon tetrachloride muddy (due to incomplete separation of water), add a few grams of anhydrous sodium sulfate, mix well and again filtered through a dry filter, collecting the filtrate in a dry dish. Keep solution in a dark bottle with a glass stopper. In the preparation of this solution allowed the use of potassium cyanide to mask interfering elements.
Lead according to GOST 3778−77*.
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* Valid GOST 3778−98. — Note the manufacturer’s database.
The solution of lead: the weight of lead weight of 100 g is dissolved in 350 cmof nitric acid (1:1). After complete dissolution of lead solution, dilute with water to 1 DM. Before use, the solution must be cleaned of copper, for which a 250 cmsolution alternately shaken with several portions of 10 cmsolution of lead diethyldithiocarbamate in chloroform or carbon tetrachloride until then, until the organic portion of the extract becomes colorless.
Copper GOST 859−78.
Standard solutions of copper.
Solution a: 0,100 g of copper is dissolved in 10 cmof nitric acid (1:1) and at weak boiling removes oxides of nitrogen. After cooling, the solution is transferred into a measuring flask with volume capacity of 1000 cm, is diluted to the mark with water and mix.
1 cmof solution A contains 0.1 mg of copper.
Solution B: 5 cmmortar And transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.
1 cmof a solution contains 0.005 mg of copper.
(Changed edition, Rev. N 1, 2).
3.2. Analysis
3.2.1. Depending on the expected mass fraction of copper take a sample of lead whose mass is listed in table.2.
Table 2
Mass fraction of copper, % |
The mass of charge, g |
The volume aliquote part of the solution, cm |
From to from 0.0002 to 0.0005 |
1,500 |
The entire volume |
SV. Of 0.0005 «to 0.002 |
1,000 |
The entire volume |
«Of 0.002» to 0.005 |
1,000 |
20 |
«0,005» 0,01 |
0,500 |
20 |
«To 0.01» to 0.05 |
0,250 |
1 |
«To 0.05» to 0.15 |
0,250 |
5 |
A portion of the lead dissolved in 10 cmof nitric acid (1:2) in the presence of 10 cmof a solution minocycli potassium-sodium salt with the mass concentration of 400 g/DM. After complete dissolution of the sample solution was boiled to remove oxides of nitrogen and the main quantity of acids. When the mass fraction of copper of more than 0,002% solution transferred to a volumetric flask with a capacity of 50 cm, is diluted to the mark with water and mix.
The whole solution or its aliquot part of the selected tab.2, containing from 3 to 25 µg of copper, is transferred into a separating funnel with a capacity of 100 cmand dilute with water to 50 cm. Add 5 cmof the solution minocycli potassium-sodium salt with the mass concentration of 400 g/DM, add 3−4 drops of solution of phenolphthalein and neutralized with an aqueous solution of ammonia prior to the dyeing solution in red. Add 10 cmof a solution of lead diethyldithiocarbamate in chloroform or carbon tetrachloride and shake for 1 min. Painted a layer of chloroform or carbon tetrachloride is transferred to a dry volumetric flask with a capacity of 25 cm. The extraction is repeated once again with 5 cmof a solution of lead diethyldithiocarbamate. The combined organic phase is diluted with chloroform or carbon tetrachloride up to the mark and mix. The solution was then filtered through a dry filter, collecting the filtrate in a dry beaker. Measure the optical density of the colored transparent filtered organic extract at a wavelength of 436 nm.
Solution comparison is chloroform or carbon tetrachloride.
At the same time carried out control experiments under the same conditions with all used during the analysis, reagents.
The amount of copper in kalorimetricheskim volume set calibration schedule.
(Changed edition, Rev.
N 2).
3.2.2. To build a calibration curve in six of the seven separatory funnels with a capacity of 100 cmis placed a solution of lead in an amount corresponding to the amount of lead in the sample solution. Added, respectively, 0.5; 1,0; 2,0; 3,0; 4,0 and 5,0 cmstandard solution B, which corresponds to 2,5; 5,0; 10,0; 15,0; 20,0 and 25,0 µg of copper. Seventh separatory funnel is used for the reference experiment. All seven funnels pour water to a volume of 50 cmand then do as stated in claim
According to the obtained values of optical density of solutions and their corresponding grades of copper to build the calibration graph.
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of copper in percent is calculated by the formula
,
where is the mass of copper was found in the calibration schedule g;
— volume of initial solution, cm;
— the weight of the portion of the lead, g;
— volume aliquote part of the solution, cm.
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.3.
Table 3
Mass fraction of copper, % |
The allowable divergence of the parallel definitions % |
Permissible discrepancies in the results of the analysis % |
From to from 0.0002 to 0.0005 « |
0,0001 |
0,0001 |
SV. Of 0.0005 «0,0010 « |
0,0003 |
0,0004 |
«0,0010» 0,0040 « |
0,0005 |
About 0.0006 |
«0,0040» 0,0100 « |
0,0010 |
0,0013 |
«0,010» 0,040 « |
0,003 |
0,004 |
«0,040» 0,150 « |
0,005 |
0,006 |
(Changed edition, Rev. N 2).