GOST 27981.4-88

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  ГОСТ 27981.4-88

GOST 27981.4−88 Copper of high purity. Methods of atomic absorption analysis

GOST 27981.4−88

Group B59

GOSUDARSTVENNYI STANDARD OF THE USSR

HIGH PURITY COPPER

Methods of atomic absorption analysis

Copper of high purity. Methods of atomic-absorption analysis

AXTU 1709

Valid from 01.01.1990
until 01.01.2000*
_______________________________
* Expiration removed
Protocol N 7−95 Interstate Council
for standardization, Metrology and certification
(IUS N 11, 1995). — Note the manufacturer’s database.

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

PERFORMERS:

B. M. Rogov, E. N. Gazalov, I., Swan, M. A. Kopanev, E. N. Gilbert, L. N. Shabanova, O. V. Romina, N. To. Baicheva, I. I. Tarasova, V. T. Yatsenko, L. V., Bonduc

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 22.12.88 N 4443

3. The term of the first check — 1994

The frequency of inspection — 5 years

4. INTRODUCED FOR THE FIRST TIME

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

_______________
* On the territory of the Russian Federation GOST 24104−2001. — Note the manufacturer’s database


This standard establishes the atomic absorption methods for the determination of elements in high purity copper as shown in table.1.

Table 1

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis and security requirements when performing the analysis according to GOST 27981.0.

1.2. Allowed the sequential determination of several elements from the same sample after appropriate dilution and selection alikvotnih parts.

2. DETERMINATION OF SILVER

(with a mass fraction of from 0.0005 to 0.005%)

The method is based on measuring the atomic absorption of the resonance lines of silver at a wavelength of 328,1 nm with the introduction of the analyzed solution into air-acetylene or propane-butane-air flame.

2.1. Equipment, reagents, solutions

Atomic absorption spectrophotometer of any type.

The hollow cathode lamp for silver.

Air compressor.

Acetylene, dissolved and gaseous technical GOST 5457.

Propane-butane according to GOST 20448*.
________________
* On the territory of the Russian Federation GOST 20448−90, here and hereafter. — Note the manufacturer’s database.

Glasses N-1−100−1-400 TCS according to GOST 25336.

Volumetric flasks 2−100−2, 2−1000−2 according GOST 1770.

5−2-10 pipettes according to GOST 20292*.
________________
* On the territory of the Russian Federation there are 29169−91 GOST, GOST 29227−91−29229−91 GOST, GOST 29251−91-GOST 29253−91, here and hereafter. — Note the manufacturer’s database.

Cylinder 1−10 according GOST 1770.

Nitric acid of high purity according to GOST 11125 or nitric acid according to GOST 4461 (not containing chlorine), diluted 1:1, and the solutions of 0.5 and 1 mol/DM.

Hydrochloric acid according to GOST 3118 and the solutions 1, 2 and 6 mol/DM.

Copper according to GOST 859*.
______________
* On the territory of the Russian Federation GOST 859−2001. — Note the manufacturer’s database.

(Pre-cleaned copper from silver in the anion exchange resin AB-17 in the chloride form according to claim 2.2.2).

A solution of 100 g/DM: a sample of copper with a mass of 10 g was dissolved with heating in 20 cmof nitric acid, diluted 1:1, and the solution is evaporated to dry salts. Then pour 10 cmof hydrochloric acid and is evaporated to dry salts. The solution was cooled, added to 16 cmof hydrochloric acid, mix, place the resulting solution in a volumetric flask with a capacity of 100 cmand adjusted to the mark with water.

Ammonium radamisty according to GOST 27067, a solution of 20 g/DM.

Silver GOST 6836* or other regulatory-technical documentation.
______________
* On the territory of the Russian Federation GOST 6836−2002, here and hereafter. — Note the manufacturer’s database.

Resin AV-17 GOST 20301.

2.2. Preparation for assay

2.2.1. Preparation of resin AB-17

A portion of the resin weight of 50 g were placed in a glass with a capacity of 400 cm, pour water and leave for a day. The water is then drained and the resin several times pour 1 M hydrochloric acid, each time pouring the solution by decantation. The last portion of the drain needs to show a negative reaction of iron with solution of ammonium Rodenstock. Then the resin is poured 1 M hydrochloric acid and stored until use.

2.2.2. Purification of copper from silver

To a solution of copper add 20−30 g of the prepared anion exchange resin AV-17 and shaken for 15 min. the Solution was filtered through a loose filter, collecting the filtrate in a volumetric flask with a capacity of 100 cm. The residue on the filter was washed with 1 M hydrochloric acid, collecting the washings in the same flask, then bring to the mark of 1 M hydrochloric acid.

The resulting solution was used as the reference experiment in the determination of silver in copper.

2.2.3. Preparation of standard solutions

Solution a: a sample of silver with a mass 0,1000 g was dissolved with heating in 10 cmof nitric acid, diluted 1:1. Then add 25 cmof water, 100−120 cmof hydrochloric acid, stirred and placed in a measuring flask with volume capacity of 1000 cmand bring to mark 6M hydrochloric acid.

1 cmof solution A contains 0.1 mg of silver.

Solution B: aliquot part 10 cmof the solution And placed in a volumetric flask with a capacity of 100 cmand bring to mark with 2 M hydrochloric acid.

1 cmof a solution contains 0.01 mg of silver.

Solution: aliquot part 5 cmof solution B is placed in a volumetric flask with a capacity of 100 cmand bring to mark with 2 M hydrochloric acid.

1 cmof the solution contains 0.005 mg of silver; the solution should be freshly prepared.

2.2.4. Construction of calibration curve

In five out of six volumetric flasks with a capacity of 100 cmis placed 1,0; 2,0; 3,0; 5,0 and 10,0 cmof solution, which corresponds to 0,005; 0,010; 0,015; 0,025 and 0,050 mg of silver. All six volumetric flasks poured 10 cmof the copper solution, for 16 cmof hydrochloric acid and was adjusted to the mark with water.

The resulting solutions are sprayed in the flame of acetylene-air or propane-butane-air and measure the absorption lines of silver at a wavelength of 328,1 nm.

According to the obtained values of optical density of solutions and their corresponding silver content build a calibration curve in rectangular coordinates.

2.3. Analysis

A sample of copper weighing 1,000 grams is placed in a beaker with a capacity of 100 cm, flow 10 cmof nitric acid, covered with a cover glass and leave you without heating until the termination of allocation of oxides of nitrogen. Then heated to dissolve the sample. Remove the glass, wash it with water over the glass and evaporate the solution to wet salts.

After cooling, add 30−40 cmof water and 16 cmof hydrochloric acid, stirred to dissolve the salt, put the solution in a volumetric flask with a capacity of 100 cmand adjusted to the mark with water.

The resulting solution is sprayed in the flame of acetylene-air or propane-butane-air and measure the absorption at a wavelength of 328,1 nm.

Measurement conditions selected in accordance with device used.

Weight of silver set calibration schedule.

2.4. Processing of the results

2.4.1. Mass fraction of silver () in percent is calculated by the formula

,

where is the mass of silver was found in the calibration schedule in the solution of the sample, mg;

 — the mass of silver found in the solution in the reference experiment, mg;

 — weight of copper,

2.4.2. Allowable absolute differences of the results of two parallel measurements at a confidence level =0.95 is (the rate of convergence) and the results of the analysis of the same samples obtained in two laboratories and one reference laboratory, but under different conditions (a measure of reproducibility) shall not exceed the permissible values given in table.2.

Table 2

2.4.3. Control of the correctness of the results of the analysis carried out on standard samples of composition of copper. The results of the analysis are considered valid if reproduced the mass fraction of component in the standard sample differs from the certified characteristics are not more than 0.71, the value of which is given in table.2.

Allowed verification of correct conduct by a method of additives according to GOST 25086. The results of the analysis are considered valid if the value found additives different from the entered values were no more than where and  — the permissible discrepancy of the two results of the analysis for the sample and the sample with the additive, respectively.

3. DETERMINATION OF MANGANESE, LEAD, IRON, ANTIMONY, BISMUTH

(at a mass fraction of from 0.0002 to 0.005%)

The method is based on measuring the atomic absorption of the resonance lines of manganese, lead, iron, antimony and bismuth with the introduction of the analyzed solution in the flame acetylene-air or propane-butane-air at wavelengths of 279.5, respectively; is 283.3; of 248.3; 217,6; 223,1 nm. The elements are pre-Coosada on the iron hydroxide or lanthanum.

3.1. Equipment, reagents, solutions

Atomic absorption spectrophotometer of any type.

The hollow cathode lamp for manganese, lead, iron, antimony, bismuth.

Air compressor.

Acetylene according to GOST 5457.

Propane-butane according to GOST 20448.

Volumetric flasks 2−25−2; 2−50−2; 2−100−2; 2−1000−2 according GOST 1770.

Reflux 250−19/26−29/32ТС according to GOST 25336.

Pipette 2−2-10, 5−2-2, 7−2-10 according to GOST 20292.

Vial 2−10−14/23 XC according GOST 1770.

Nitric acid of high purity according to GOST 11125 or nitric acid according to GOST 4461 (distilled in quartz apparatus), diluted 1:1, 1:4; solutions of 0.1 and 0.02 mol/DM.

Hydrochloric acid of high purity according to GOST 14261, or hydrochloric acid according to GOST 3118, diluted 1:1, 1:5, 7:3, a solution of 2 mol/DM.

Sulfuric acid according to GOST 4204, diluted 1:10.

Ammonia water according to GOST 3760 and diluted 1:19.

Iron according to GOST 9849, a solution of 15 g/DMin 0.1 M nitric acid.

Hydrogen peroxide according to GOST 10929, diluted 1:10.

Lanthanum chloride or nitrate, or lanthanum oxide; the solution containing 2 mg of lanthanum in 1 cm: linkage of lanthanum nitrate with a mass of 3.1 grams, or lanthanum oxide by weight 2.4; or chloride of lanthanum weighing 5.4 g was dissolved in 10−15 cmof hydrochloric acid diluted 1:1, the resulting solution placed in a measuring flask with volume capacity of 1000 cmand was adjusted to the mark with water.

Bismuth GOST 10928* brand Vi00 or Ви0.
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* On the territory of the Russian Federation GOST 10928−90, here and hereafter. — Note the manufacturer’s database.

Manganese metal according to GOST 6008*.
______________
* On the territory of the Russian Federation GOST 6008−90. — Note the manufacturer’s database.

Lead of high purity according to GOST 22861* or lead according to GOST 3778** stamps S00.
______________
* On the territory of the Russian Federation GOST 22861−93;
** On the territory of the Russian Federation GOST 3778−98. — Note the manufacturer’s database.

Antimony GOST 1089.

Trioxide of antimony.

The bidistilled or deionized water.

3.2. Preparation for assay

3.2.1. Preparation of standard solutions

3.2.1.1. Manganese.

Solution a: a portion of the manganese weight 0,100 g dissolved in 20 cmof nitric acid, diluted 1:1, cooled, placed in a volumetric flask with a capacity of 1000 cmand was adjusted to the mark with water.

1 cmof solution A contains 0.1 mg of manganese.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, add 1 cmof nitric acid, diluted 1:1, and adjusted to the mark with water.

1 cmof a solution contains 0.01 mg of manganese.

Solution In 20 cmof solution B is placed in a volumetric flask with a capacity of 100 cm, add 3 cmof nitric acid, diluted 1:1, and adjusted to the mark with water.

1 cmof the solution contains 0.002 mg of manganese.

3.2.1.2 Lead.

Solution a: a sample of lead weighing 0,100 g dissolved in 10 cmof nitric acid, diluted 1:1. The solution is placed in a measuring flask with volume capacity of 1000 cmand was adjusted to the mark with water.

1 cmof solution A contains 0.1 mg of lead.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cmand adjusted to the mark with water.

1 cmof a solution contains 0.01 mg of lead.

Solution In 20 cmof solution B is placed in a volumetric flask with a capacity of 100 cmand adjusted to the mark with water.

1 cmof the solution contains 0.002 mg of lead.

3.2.1.3. Iron.

Solution a: a sample of iron weighing 0,100 g dissolved in 20 cmof hydrochloric acid diluted 1:1, when heated. The solution was then cooled, placed in a volumetric flask with a capacity of 1000 cmand was adjusted to the mark with water.

1 cmof solution A contains 0.1 mg of iron.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, add 10 cm0.1 M nitric acid and adjusted to the mark with water.

1 cmof a solution contains 0.01 mg of iron.

Solution In 20 cmof solution B is placed in a volumetric flask with a capacity of 100 cm, add 10 cm0.1 M nitric acid and adjusted to the mark with water.

1 cmof the solution contains 0.002 mg of iron.

3.2.1.4. Antimony.

Solution a: a portion of the antimony by weight 0,100 g was placed in a conical flask with a capacity of 250 cm, flow 20 cmof sulfuric acid and heated to dissolve sample. After cooling, add 100−150 cmof water, stirred, cooled, placed in a volumetric flask with a capacity of 1000 cmand was adjusted to the mark with sulfuric acid diluted 1:10. In the preparation of the solution And antimony trioxide hitch weight 0,120 g is placed in a conical flask with a capacity of 1000 cm, equipped with a reflux condenser. Pour 200cmof hydrochloric acid diluted 7:3, and heated to dissolve sample. After cooling, the solution is evaporated to a volume of 5−10 cm, placed in a volumetric flask with a capacity of 1000 cmand was adjusted to the mark with sulfuric acid diluted 1:10.

1 cmof solution A contains 0.1 mg of antimony.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cmand adjusted to the mark with sulfuric acid diluted 1:10. Use freshly prepared solution.

1 cmof solution B contains 0.01 g of antimony.

Solution In 20 cmof solution B is placed in a volumetric flask with a capacity of 100 cmand adjusted to the mark with sulfuric acid diluted 1:10. Use freshly prepared solution.

1 cmof the solution contains 0.002 mg of antimony.

3.2.1.5. Bismuth.

Solution a: a sample of bismuth by weight dissolve 0,100 g with heating in 5 cmof hydrochloric acid diluted 1:5. After cooling, pour the 50−80 cmof water, stirred to dissolve the salts, placed in a volumetric flask with a capacity of 1000 cmand was adjusted to the mark with nitric acid, diluted 1:1.

1 cmof solution A contains 0.1 mg of bismuth.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cmand adjusted to the mark with 0.1 M nitric acid.

1 cmof a solution contains 0.01 mg of bismuth.

3.2.2. Construction of calibration graphs

For constructing the calibration graphs to the number of beakers (and conical flasks) put 0,0; 1,0; 2,0; 5,0; 10,0 cmstandard solution of manganese and 5.0; 10.0 cmof a standard solution of manganese is Used, which corresponds to 0,0; 0,002; 0,004; 0,010; 0,020; 0,050 and 0,100 mg manganese; 1,0; 2,0, 5,0; 10,0 cmstandard solution lead; 5,0; 10,0 cmstandard solution of lead B, which corresponds to 0,002; 0,004; 0,010; 0,020; 0,050; 0,100 mg of lead; 1,0; 2,0; 5,0; 10,0 cmstandard solution of iron, which corresponds to 0,002; 0,004; 0,010; 0,020 mg of iron; 1,0; 3,0; 5,0 cm of a standard solution of antimony In and 3,0; 5,0; 10,0 cmstandard solution of antimony B, which corresponds to 0,0; 0,002; 0,006; 0,010; 0,030; 0,050; 0,100 mg of antimony; 0,5; 1,0; 2,5; 5,0; 7,5; 10,0 cmstandard solution of bismuth B, which corresponds to 0,005; 0,010; 0,025; 0,050; 0,075; 0,100 mg of bismuth.

In all the cups (or flasks) pour 3 cmof a solution of lanthanum or iron (in beakers containing the standard iron solution, and pour 3 cmof a solution of lanthanum), add 5−10 cmof nitric acid, diluted 1:1, 3−5 cmof 30% hydrogen peroxide solution, 80−100 cmof water and heat the solution to boiling. In a solution of ammonia is added to the precipitation of iron hydroxide or lanthanum and 5 cm. Aged solution to precipitate at a temperature of 60−70 °C to coagulate the precipitate. It is then filtered through a medium density filter and washed precipitate on the filter 4−5 times a hot ammonia diluted 1:19.

The filter cake is dissolved in 10−15 cmof hot hydrochloric acid, diluted 1:1 (hydroxide precipitate with lead is dissolved in hot nitric acid, diluted 1:1). Washed the filter with hot water until neutral wash water (universal indicator paper), collecting the filtrate in the beaker (or flask), which conducted the deposition. The solution is evaporated under heating to a volume of 6−8 cm, cooled, put the solution into a measuring beaker with a capacity of 10 cmor volumetric flask with a capacity of 25 cmdepending on the weight of the items and bring to mark with water.

Spray the solutions in the flame acetylene-air or propane-butane-air and measure the absorption of the resonant lines of elements with wavelengths of manganese 279,5 nm, of lead is 283.3 nm, for iron is of 248.3 nm, antimony 217,6 nm, bismuth — 223,1 nm.

According to the obtained values of optical densities and corresponding concentrations of elements in standard solutions to build calibration graphs in rectangular coordinates, using for each point the average value of two optical density measurements.

3.3. Analysis

3.3.1. To remove particles of iron (perhaps introduced during the preparation of samples for analysis) shavings of copper is treated with a magnet. Then the chip is washed with 5−10 cmof hydrochloric acid diluted 1:10, and twice in double-distilled (or deionized) water.

3.3.2. A sample of copper with a mass of 2,000 g were placed in a glass (or conical flask) with a capacity of 250 cmand 20−25 cm pournitric acid, diluted 1:1. Heated to dissolve the sample. Then pour 100 cmwater, 10 cmof a solution of lanthanum, of 3−5 cmof 30% hydrogen peroxide solution and heat the solution to boiling. The solution was added ammonia in such quantity that the whole of the copper passed into the ammonia complex and 5 cm. Stand the beaker (or flask) in a warm place plate to the coagulation of the precipitate.

Filter the solution through a medium density filter and washed precipitate on the filter 4−5 times a hot ammonia diluted 1:19.

Then the filter cake is dissolved in 10−15 cmof hot nitric acid diluted 1:1, and washed the filter with hot water until neutral wash water (universal indicator paper), collecting the filtrate in the beaker (or flask), which conducted the deposition. The solution is evaporated to a volume of 6−8 cm, cooled, placed in a measuring tube with a capacity of 10 cmor volumetric flask with a capacity of 25 cmdepending on the mass percentage of the elements and adjusted to the mark with water.

Spray the analyzed solutions, the solutions in the reference experiment and the solutions for constructing the calibration graphs in the flame acetylene-air or propane-butane-air and measure the absorption of the resonance lines of the elements. A lot of elements determined by a calibration chart.

Measurement conditions selected in accordance with device used.

3.4. Processing of the results

3.4.1. Mass fraction of element (a) in percent is calculated by the formula

,

where is the concentration of the analyzed element in the sample solution found by the calibration schedule, mg/cm;

 — the concentration of the element in solution in the reference experiment, mg/cm;

the capacity of volumetric flasks (vials), cm;

 — weight of copper,

3.4.2. Allowable absolute differences of the results of two parallel measurements at a confidence level =0.95 is (the rate of convergence) and the results of the analysis of the same samples obtained in two laboratories and one reference laboratory, but under different conditions (a measure of reproducibility) shall not exceed the permissible values given in table.3.

Table 3

3.4.3. Control of the correctness of the analysis results according to claim 2.4.3.

4. DETERMINATION OF SELENIUM AND TELLURIUM

4.1. Determination of selenium (at a weight ratio 0,00002−0,0005%)

Carried out determination of selenium atomic absorption method with electrothermal atomizer at the analytical line 196,0 nm after dissolution of sample of copper in nitric acid and solvent extraction with toluene concentration of selenium from the test solution containing 8 mol/DMof hydrochloric acid 2 mol/lperchloric acid, 0.2 mol/DMbromatological acid and 50 g/cmof copper.

4.1.1. Equipment, reagents, solutions

Atomic absorption spectrophotometer model 503 of the firm Perkin-Elmer electrothermal atomizer (ETA) brand HGA-76 or apparatus of the same type.

Argon gas of the highest grade according to GOST 10157.

The air compressed under a pressure of 2·10-6·10PA (2−6 kg/cm).

Lamp hollow cathode or electrodeless (with power supply) for selenium.

Analytical scale any type of 2nd class of accuracy.

Glasses N-1−100 TCS according to GOST 25336.

Volumetric flasks 2−50−2, 2−100−2 according GOST 1770.

Pipette 5−2-1, 5−2-2, 5−2-5 according to GOST 20292.

Cylinder 1−10 according to GOST 1770−74.

Vials P-2−10−0,2 CH, P-2−20−0,2 CH, P-2−25−0,2 KHS GOST 1770.

Eppendorf pipette with a capacity of 0.02 cm.

Thermometer.

Selenium according to normative-technical documentation.

Nitric acid according to GOST 4461, diluted 1:1.

Hydrochloric acid according to GOST 3118.

Bromatologia acid according to GOST 2062.

Perchloric acid (57% solution).

Toluene according to GOST 5789.

The technical rectified ethyl alcohol according to GOST 18300.

4.1.2. Preparations for the analysis

4.1.2.1. Preparation of solutions comparison (PC)

Solution a: a sample of selenium metal weight 0,100 g dissolved in a mixture of 10−15 cmof hydrochloric acid and 0.1−0.2 cmof nitric acid by heating on a water bath until complete dissolution of selenium. The cooled solution is placed in a measuring flask with volume capacity of 1000 cm, made up to the mark with hydrochloric acid so that the final solution contained 6 mol/DMof hydrochloric acid.

1 cmof the solution contains 1 mg selenium.

Solution B: 2 cmof solution A were placed in a glass with a capacity of 100 cm, flow 10 cmof perchloric acid and heated in a water bath until fumes of perchloric acid. The glass is removed from the water bath, cooled, washed the side of the Cup with water and repeat evaporation to fumes of perchloric acid. The solution is placed in a volumetric flask with a capacity of 100 cmwith 10−15 cmof water, bring to the mark with hydrochloric acid.

1 cmof solution B contains 20 mcg of selenium.

Solution: 1 cmof solution B was placed in a vial with a capacity of 25 cm, pour 2 cmof perchloric acid, adjusted to the mark 9 cmwith hydrochloric acid, add 0.3 cmbromatological acid, 10 cmof toluene. Extracted 15 min. a Solution contains 1 cm2 mcg of selenium.

4.1.2.2. Solutions for atomic absorption analysis (at least three).

1 cmof solution was placed in a vial with a capacity of 10 cmand 9 cm is addedtoluene (solution G).

In two test tubes with a capacity of 10 cmwas placed 1 cmsolution G, poured into one 3 and the other 1 cmof toluene. Solutions are, respectively, the concentration of selenium 0.05 and 0.1; solution G — 0,2 µg/cm.

4.1.2.3. Preparation and certification of synthetic mixtures for validation of the technique and the correct operation of the device.

Take away 2.5 cmof solution B prepared according to claim 4.1.2.1, and placed in a volumetric flask with a capacity of 100 cmand adjusted to the mark with water.

1 cmof the mixture contains 0.5 mcg of selenium. The error introduced selenium content of not more than 2%.

Certified the mixture is an aqueous solution containing selenium with a concentration of (0,5±0,02) mkg/cm. The mixture is prepared before use.

4.1.2.4. Preparation of measuring equipment.

The inclusion and configuration of the device and THIS is carried out in accordance with the manual.

The correct operation of the device and the position of the calibration chart, checking, inspecting a synthetic mixture prepared in accordance with clause 4.1.2.3. Analytical signal with the introduction of 0.02 cmof a solution containing 0.5 µg/cmof selenium should be about 0.2 units of absorbance.

Use analytical line 196,0 nm; the slit of 2.0 nm and the mode of operation of THIS are shown in table.4.

Table 4

Note. When working with the similar device of another brand of the test you are correct, based on the maximum analytical signal in the analysis of selenium in one PC.


When using devices of other brands of analytical signal with the introduction of the synthetic compound must match the value given in the passport on this device.

Eppendorf pipette with a capacity of 0.02 cmis introduced into the toluene, and by varying the decomposition temperature from 700 to 900 °C to ensure that the absorption signal of toluene were no more than the simple firing of the cell. This operation is performed for each graphite tube.

4.1.3. Analysis

4.1.3.1 Weighed sample of copper weighing 1,000 grams is placed in a beaker with a capacity of 100 cm, 10−15 cm pournitric acid, diluted 1:1, and heat the solution to dissolve the sample. The solution is evaporated to 5−6 cm, pour the 7 cmof perchloric acid. Heated until the appearance of fumes of perchloric acid and removed the beaker from the plate; cool, add ~3 cmof water and again heated until the appearance of white vapors. The solution is cooled to a temperature of 30−50 °C, pour 10 cmof hydrochloric acid, is heated to a temperature not higher than 50 °C, stirring to complete or partial dissolution of salts. The content was transferred into a test tube with a capacity of 20 cm(or 25 cm), washed with a glass of 0,5−1 cmof water and hydrochloric acid, added to vial 0.6 cmbromatological acid and adjusted to the mark 20 cmof hydrochloric acid. Stirred to dissolve the solids, opening the vial each time after 2−4 shakes.

In a test tube with a capacity of 10 cmis placed 2 cmextractant and 2 cmof sample solution for the expected contents of selenium (2−5)·10% (ratio of volumes of organic and aqueous phases 1:1) or 4 cmof sample solution for the expected content of selenium less than 2·10% (ratio of phases 1:2) and extracted for 15 min. the Extract should be colorless, aqueous phase dark brown. Phases do not divide; to analyze use the extract.

4.1.3.2. Aliquote part PC, of the sample solution and the reference experiment with a volume of 0.02 cmsuccessively introduced in THIS. The absorption signal is recorded using the recorder. When writing to celebrate the start of atomization of selenium in the OS. If the start signal of selenium in the sample it is difficult to distinguish on the background of the recording, increase the speed of drawing paper. For each solution make 2−3 measurements. After every 5−8 samples analyzed on one PC. Periodically, 2−3 hours, wipe it with cotton wool moistened with alcohol, glass atomizer and graphite contacts THIS. After cleaning, carry out the firing of the graphite tube.

4.1.4. Processing of the results

4.1.4.1. Mass fraction of selenium () in percent is calculated by the formula

,

where the conversion factor is equal to:

=1·10(at volume ratio of phases 1:2)

=2·10(in the volume ratio of phases 1:1);

 — the height of the peak absorption of selenium in the solution of the sample, mm;

 — calibration factor ,

where  — number PC;

 — the concentration of selenium in m PC, µg/cm;

 — the height of the peak absorption of selenium in m PC.

Mass fraction of selenium in the analyzed test () in % are also determined by the calibration chart, on the x-axis which lay in the concentration of selenium in PC multiplied by 1·10(at a ratio of phases 1:2) or 2·10(at a ratio of phase 1:1), on the y — axis the average value of the heights of the corresponding peaks of absorption.

4.1.4.2. Allowable absolute differences of the results of two parallel measurements (the rate of convergence) and the results of the analysis of the same samples obtained in two laboratories and one reference laboratory, but under different conditions (a measure of reproducibility) shall not exceed the values given in table.5.

Table 5

Note. The values of permissible variances for interval interval is calculated by linear interpolation.

4.1.4.3. Control of the correctness of the analysis results according to claim 2.4.3.

4.2. Determination of tellurium (if the mass fraction of 0,00001−0,0002%)

The definition of tellurium is carried out by atomic absorption method with electrothermal atomizer at the wavelength 214,3 nm after dissolution of sample of copper in hydrochloric acid and hydrogen peroxide extraction and concentration of tellurium in solution of 0.05 M of trialkylaluminium in toluene from the test solution containing 3−6 mol/DMof hydrochloric acid and 50 g/cmof copper.

4.2.1. Equipment, reagents, solutions

Atomic absorption spectrophotometer model 503 of the firm Perkin-Elmer. Electrothermal atomizer HGA-brand-76 or apparatus of the same type.

Argon gas of the highest grade according to GOST 10157.

The air compressed under a pressure of 2·10-6·10PA (2−6 kg/cm).

Lamp hollow cathode or electrodeless (with power supply) for tellurium.

Footwear any type of 2nd class of accuracy.

Glasses N-1−100 TCS according to GOST 25336.

Volumetric flasks 2−50−2, 2−100−2 according GOST 1770.

Pipette 5−2-2, 5−2-5 according to GOST 20292.

Vials P-2−10−02 KHS GOST 1770.

Eppendorf pipette with a capacity of 0.02 cm.

Cylinders with a capacity of 10 and 50 cmaccording to GOST 1770.

Tellurium of high purity according to normative-technical documentation.

Nitric acid according to GOST 4461, diluted 1:1.

Hydrochloric acid according to GOST 3118.

Toluene according to GOST 5789.

The technical rectified ethyl alcohol according to GOST 18300.

Trialkylaluminium (TABS), the extractant; 0.05 M solution in toluene: to a dry capacity of at least 1 DMcarry 42 cmtechnical TABS and 960 cmtoluene, washing them with a measuring glass (cylinder) from under the TABS.

Hydrogen peroxide according to GOST 10929, stable product.

4.2.2. Preparations for the analysis

4.2.2.1. Sample preparation comparison (PC)

Solution a: a suspension of metallic tellurium with a mass of 0.010 g was placed in a beaker and dissolved in 5−10 cmof nitric acid, diluted 1:1 by heating to complete decomposition of the sample. In a volumetric flask with a capacity of 100 cmpour 50 cmof hydrochloric acid, poured the cooled solution from a glass, washing it with water and bring to the mark with water. 1 cmof solution A contains 0.1 mg of tellurium.

Solution B: 1.0 cmof solution A is placed in a volumetric flask with a capacity of 50 cmand was adjusted to the mark with hydrochloric acid diluted 1:1.

1 cmof solution B contains 2 mg of tellurium.

Solution: 2.5 cmof solution B is placed in a volumetric flask with a capacity of 100 cmand adjusted to the mark with hydrochloric acid diluted 1:1.

1 cmof the solution contains 0.05 mg of tellurium.

Solutions comparison (PC) for atomic absorption analysis (at least three): three-dimensional tubes with a capacity of 10 cmplaced 1, 2 and 4 cmof solution, poured at ~0.4 cmof any of the raffinate samples (prepared according to claim 4.2.3), adjusted with hydrochloric acid diluted 1:1 to the volume of 4 cmand add 2cmextractant. Extracted 15 min. the Extracts contain 0,025; 0.05 and 0.1 micrograms/cm.of tellurium.

4.2.2.2. Preparation of certified mixtures for validation of the technique and the correct operation of the device.

5 cmof solution B prepared according to claim 4.2.2.1, is placed in a volumetric flask with a capacity of 50 cmand was adjusted to the mark with water.

1 cmof the prepared mixture contains 0.2 micrograms of tellurium. The error introduced in the content of tellurium is not more than 2%.

Certified the mixture is an aqueous solution containing the tellurium with a concentration of (0,200±0,004) µg/cm.

4.2.2.3. Preparation of measuring equipment

The inclusion and configuration of the device and THIS is carried out in accordance with the manual.

Check the correct operation of the device, using a certified mixture made according to claim 4.2.2.2.

Use analytical line 214,3 nm; slit 0.2 nm and the mode of operation of THIS are shown in table.6.

Table 6

Eppendorf pipette with a capacity of 0.02 cmis introduced into the solution of the extractant in toluene and varying the decomposition temperature of 800 to 1000 °C to ensure that the absorption signal of the solution was not more than the firing of the cell. This operation is performed for each graphite tube.

4.2.3. Analysis

4.2.3.1. Sample preparation

Weighed sample of copper weighing 0,500 g was placed in a beaker with a capacity of 100 cm, pipette add 4.2 cmof hydrochloric acid, covered with a cover glass (lid) and add 3 cmof 30% hydrogen peroxide solution. To speed up the reaction mixture is shaken 3−5 times. After termination of the reaction (bubbling) 5−8 min, add another 4 cmof hydrogen peroxide, shaken 3−5 times. After dissolution of sample of copper glass put on the stove, the solution is brought to a boil and after 2−3 minutes the glass after decomposition of the excess peroxide is removed from the plate, cooled and the volume was adjusted to 10 cmwater.

In a test tube with a capacity of 10 cmmaking a 2 cmextractant and 2 cmof sample solution for the expected content of tellurium (1−2)·10% (ratio of volumes of organic and aqueous phases 1:1) or 4 cmof sample solution for the expected content of tellurium is less than 1·10% (ratio of phases 1:2). Extracted 15 min. the Phases are not divided, for the analysis to use the extract.

4.2.3.2. Measurements

Aliquote part PC, trial and solution control experience volume of 0.02 cmsuccessively introduced in THIS. The absorbance signal of tellurium recorded using the recorder. For each solution make 2−3 parallel measurements of the signal. After every 5−8 samples analyzed on one PC. THIS glass after 2−3 hours wipe the cotton wool moistened with alcohol and then dry with a cotton cloth. At the end, wipe the cotton wool moistened with alcohol, the graphite contacts THIS.

4.2.4. Processing of the results

4.2.4.1. Mass fraction of tellurium () in percent is calculated by the formula

,

where the peak height absorbance of tellurium in the solution of the sample, mm;

 — calibration factor , where  — number PC;

 — the concentration of tellurium in -m PC, µg/cm;

 — the peak height, mm.

the conversion factor is equal to 1·10(at volume ratio of phases 1:2) and 2·10(1:1).

Mass fraction of tellurium in the sample () in percentage can also be found on the calibration chart, on the x-axis which lay concentration of tellurium in the PC, multiplied by 2·10(at a ratio of phase 1:1), or 1·10(at a ratio of 1.2), and on ordinate axis — the average value of the heights of the corresponding peaks of absorption.

4.2.4.2. Allowable absolute differences of the results of two parallel measurements (the rate of convergence) the results of the analysis of the same samples obtained in two laboratories and one reference laboratory, but under different conditions (a measure of reproducibility) shall not exceed the values given in table.7.

Table 7

Note. The values of permissible variances for interval interval is calculated by linear interpolation.

4.2.4.3. Control of the correctness of the analysis results according to claim 2.4.3.

5. DETERMINATION OF BISMUTH, TIN AND SILVER

(when the mass fraction of bismuth from 0.00001 to 0.0005% of the tin is from 0.00001 to 0.0005%, silver from 0,0002 to 0,003%)

The method includes the acid decomposition of sample sample extraction of bismuth, tin, silver solution trialkylborane chloride (TABS) in toluene and subsequent atomic absorption determination of bismuth, tin, silver in the organic phase. The atomization of samples in the determination of bismuth and tin is in the electrothermal atomizer, in the determination of silver — flame «acetylene-air».

5.1. Equipment, reagents, solutions

Spectrophotometer atomic absorption of the company «Hitachi» with electrothermal atomizer or firm Perkin-Elmer, model 403.

Lamps hollow cathode for bismuth, tin, silver.

The apparatus for mixing fluids of the type AVB-4P or a similar type.

Laboratory scales analytical any type of 2nd class of accuracy.

The funnel type of CH according to GOST 25336.

Funnel separating VD-1−1000 GOST 25336.

Volumetric flasks 2−50−2, 2−100−2, 1−500−2, 2−1000−2 according GOST 1770.

Vials P-2−100−29/32 KHS GOST 1770.

Pipettes 1−2-1, 1−2-2, 2−2-5, 2−2-10, 2−2-25, 2−2-50, 4−2-1, 4−2-2, 5−2-2 according to GOST 20292.

The glasses In the-1−100 TC GOST 25336.

Eppendorf pipette with a capacity of 0.02 cm.

Nitric acid of high purity according to GOST 11125, diluted 1:1.

Sulfuric acid of high purity according to GOST 14262, diluted 1:1, 1:17.

Hydrochloric acid of high purity according to GOST 14261, diluted 1:5, 1:10, 1:100.

Ammonia water according to GOST 3760, diluted 1:1.

Silver GOST 6836 or other regulatory-technical documentation.

Tin GOST 860.

Bismuth GOST 10928.

The technical rectified ethyl alcohol according to GOST 18300.

Toluene according to GOST 5789.

Acetylene, dissolved and gaseous GOST 5457.

Trialkylborane chloride (TABS), a 1.3 mol/DM; solution of 0.26 mol/lin toluene.

Distilled water according to GOST 6709, deionised water obtained by passing through ion exchange column with cation exchange resin, for example, KU-2−8.

Cation exchange resin KU-2−8 according to GOST 20298.

Argon gaseous and liquid GOST 10157.

Detergents, synthetic powder according to GOST 25644*.
______________
* On the territory of the Russian Federation GOST 25644−96. — Note the manufacturer’s database.

5.2. Preparations for the analysis

5.2.1. Preparation of the solution the TABS of 0.26 mol/lin toluene TABAH (1.3 mol/DM) was diluted with toluene in a ratio of 1:4 was placed in a separatory funnel and washed twice with in 4−5 min an equal volume of ammonia, diluted 1:1. To defend the complete separation of fractions. Then washed with water, hydrochloric acid, diluted 1:5 and twice with hydrochloric acid, diluted 1:100. Check the acidity of the aqueous phase, the pH should be equal to 1−2. At pH more than two repeat the washing with hydrochloric acid diluted 1:5, then with hydrochloric acid, diluted 1:100.

5.2.2. Preparation of standard solutions

5.2.2.1. Preparation of a standard solution of bismuth

A portion of the metal bismuth weight 0,100 g were placed in a glass with a capacity of 100 cm, is dissolved in 10 cmof nitric acid, diluted 1:1, evaporated with 5 cmof sulphuric acid until white fumes, cooled, placed in a volumetric flask with a capacity of 1000 cmand was adjusted to the mark with sulfuric acid, diluted 1:17.

1 cmof the solution contains 0.10 mg of bismuth.

5.2.2.2. Preparation of a standard solution of tin

The hitch tin metal weight 0,100 g were placed in a glass with a capacity of 100 cm, dissolved in 20 cmof hydrochloric acid by heating on a sand bath, not boiling, cooled, placed in a volumetric flask with a capacity of 1000 cmand was adjusted to the mark with water.

1 cmof the solution contains 0.10 mg of tin.

5.2.2.3. Preparation of a standard solution of silver

A portion of metallic silver weighing 0,100 g were placed in a glass with a capacity of 100 cm, is dissolved in 10 cmof nitric acid, diluted 1:1 was placed in a volumetric flask with a capacity of 1000 cmand was adjusted to the mark with water.

1 cmof the solution contains 0.10 mg of silver.

5.2.3. Preparation of working standard solutions

5.2.3.1. Preparation of working standard solutions of bismuth and tin

In a volumetric flask with a capacity of 500 cmmake 5 cmstandard solutions of bismuth and tin and bring to the mark with hydrochloric acid diluted 1:10. Then with a pipette take 50 cmof the solution was placed in a vial with a capacity of 100 cmand perform the extraction with an equal volume of the solution TABS for 30 min in the apparatus for fluid mixing. 1 cmof the extract contains 1 µg of bismuth and tin.

In a volumetric flask with a capacity of 25 cmmake of 0.50; 1,25; 2,50; 5,00; 12,50 cmof the extract and bring to mark with a solution of the TABS. Working standard solutions containing 0,02; 0,05; 0,10; 0,20; 0,50 µg/cmof bismuth and tin.

5.2.3.2. Preparation of working standard solutions of silver

In a volumetric flask with a capacity of 500 cm tomake 50 cmof standard silver solution and adjusted to the mark with hydrochloric acid diluted 1:10. Pipette take 50 cmof the solution was placed in a vial with a capacity of 100 cmand perform the extraction with an equal volume of the solution TABS for 30 min in the apparatus for fluid mixing. The extract contains 10 µg/cmof silver.

In a volumetric flask with a capacity of 50 cmmake 0,50; 1,25; 2,50; 5,00; 10,00; 15,00 cmextract and bring to mark with a solution of the TABS. Working standard solutions contain 0,10; 0,25; 0,50; 1,00; 2,00; 3,00 mg/cmof silver.

Working standard solutions are stable for four days.

5.2.4. Construction of calibration graphs

The calibration graphs built using a computing device «electronics-60», a device of a different type, or manually.

For constructing the calibration graphs to measure the absorbance of the working standard solutions at the beginning and end of the electrophoretic batch of samples and average values of absorbance and corresponding mass concentrations to build calibration graphs in rectangular coordinates.

Fotometrirovanie of each solution is performed at least two times.

5.2.5. Preparation of instruments for measuring

5.2.5.1. The conditions of measurements and preparatory work required to bring the spectrophotometers in a working condition — user manual.

5.2.5.2. The electrophoretic conditions for the spectrophotometer of the firm «Perkin-Elmer» are given in table.8.

Table 8

5.2.5.3. The electrophoretic conditions for the spectrophotometer of the firm «Hitachi» is shown in table.9.

Table 9

Stages and conditions of process of atomization of the sample in a graphite cuvette are given in table.10.

Table 10

Temperature for the electrothermal atomizer

(when stationary gas flow)

5.3. Analysis

5.3.1. A portion of the sample with a mass of 1,000 g was placed in a beaker with a capacity of 100 cmand dissolved by heating in 15 cmof nitric acid, diluted 1:1, evaporated to wet salts. Pour the 7 cmof sulphuric acid diluted 1:1, and is evaporated until the appearance of sulphuric acid fumes. The residue is cooled and dissolved by heating in 10 cmof hydrochloric acid, diluted 1:100, transferred to a volumetric flask with a capacity of 50 cm, the glass is washed with 5−7 cmof hydrochloric acid, diluted 1:100, and added to the solution in a volumetric flask. With a pipette add 2 cmof a solution of the TABS and perform the extraction on the apparatus for mixing for 30 min. After complete separation the organic phase is raised into the narrow part of the flask by adding 20 cmof hydrochloric acid, diluted 1:100.

5.3.2. To determine the mass concentration of silver lower the capillary into the flask with the extract and hold fotometricheskie according to claim 5.2.5.2. The capillary and the spray system after each electrophoretic washed with a solution of Tabaha for 10−15 s. At the end of the electrophoretic batch of samples, the capillary and the spray system was washed with 8−10 cmof ethanol.

5.3.3. Eppendorf pipette of 0.02 cmof the analyzed solution of bismuth or tin is transferred to a double-annealed graphite cuvette and photometered according to claim 5.2.5.3.

After eight to ten measurements carried out the operation of firing and venting the cell.

5.3.4. Simultaneously with the analysis of spend control experience for inclusion in the analysis result of the amendment, taking into account the mass fraction of detectable elements in the reagents and materials. The correction is calculated as arithmetic mean of three parallel measurements.

5.4. Processing of the results

5.4.1. The calculation is carried out on a computing device «Elektronika-60».

5.4.2. Mass fraction of bismuth, tin and silver () in percent is calculated by the formula

, (1)

where is the mass concentration of element in solution in the reference experiment; ág/cm;

 — mass concentration of the element was found in the calibration schedule, µg/cm;

 — volume fotometricheskogo extract, cm;

 — the weight of the portion of the sample,

5.4.3. The final result of the analysis be the arithmetic mean of measurements of concentration in the three batches of samples. Averaging subject results, differing by an amount not greater

, (2)

where .

The coefficients and are given in table.11.

Table 11

Upon receipt of the results of parallel measurements with discrepancies in excess of permissible, analysis of samples is repeated.

If you re analysis of this requirement is not met, then repeat sampling.

If unsatisfactory re-evaluation for analysis by this technique stops to identify and eliminate the causes of deviation.

5.4.4. The decision about the satisfactory reproducibility of the analyses take if the discrepancy between the results of primary and repeated tests at a confidence level =0.95 does not exceed the values calculated by the formula 3

, (3)

where and  — coefficients in accordance with table.11;

 — the arithmetic mean of the results of the analysis, %.

5.4.5. Control of the correctness of the results of the analysis carried out — according to claim 2.4.3