GOST 22519.5-77

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  ГОСТ 22519.5-77

GOST 22519.5−77 Thallium. Method for the determination of copper, cadmium and zinc (with Amendments No. 1, 2, 3)

GOST 22519.5−77

Group B59

STATE STANDARD OF THE USSR

THALLIUM

Method for the determination of copper, cadmium and zinc

THALLIUM. Method for the determination of copper, cadmium and zink

AXTU 1709

Date of introduction 1978−01−01

INFORMATION DATA

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

DEVELOPERS

A. P. Sychev, M. G. Sun, V. I. Lysenko, I. A. Romanenko, V. A. Kolesnikov

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 10.05.77 N 1171

Change No. 3 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 4 dated 21.10.93)

The adoption voted:

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken on the Protocol, the Interstate Council for standardization, Metrology and certification (ICS 2−93)

6. REPRINT (February 1998) with Amendments No. 1, 2, 3, approved in January 1983, March 1987-June 1996 (IUS 5−83, 6−87, 9−96)


This standard sets the polarographic method for the determination of copper (at a mass fraction of copper from 0,000005 to 0.003%), cadmium (at a mass fraction of cadmium from 0,000005 to 0.003%) and zinc (when the mass fraction of zinc from 0,000005 to 0.003%) in waist brands Tl00, TL0 and TL1 GOST 18337*.
______________
* On the territory of the Russian Federation GOST 18337−95. — Note the manufacturer’s database.

The method is based on the separation of thallium (III) extraction dichloroethylene with ether (hloreksa), tellurium (IV) by methyl isobutyl ketone from the acid solutions bromatological 3−4 mol/DMand polarographic determination of copper, cadmium and zinc on the background of the containing ammonia and ammonium chloride, in the presence of sodium sulfite, within the polarization dripping mercuric electrode from minus 0.3 to minus 1.6 V relative to a saturated calomel or mercury electrodes in the internal comparison.

(Changed edition, Rev. N 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis and security requirements — according to GOST 22519.0.

(Changed edition, Rev. N 3).

2. APPARATUS, REAGENTS AND SOLUTIONS

Polarograph polarograph oscilloscope or AC of any type.

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

Hydrochloric acid according to GOST 3118 and diluted 2:1.

Bromatologia acid according to GOST 2062.

Perchloric acid, 57% solution (8.5 mol/DM).

Ammonia water according to GOST 3760.

Ammonium chloride according to GOST 3773.

Bromine according to GOST 4109.

Copper according to GOST 859* brand M00.
______________
* On the territory of the Russian Federation GOST 859−2001. — Note the manufacturer’s database.

Sanitarily sodium (sodium sulfite).

Cadmium GOST 1467, brand Кд0.

Mercury GOST 4658.

Zinc metal granulated.

Standard solutions of copper.

Solution A, prepared as follows: a sample of copper weighing 0,100 g dissolved in 10 cmof nitric acid and evaporated to dryness. Pour 2 cmof hydrochloric acid and again evaporated to dryness. Pour 50 cmof hydrochloric acid, 200 cmof water, quantitatively transferred to a volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.

1 cmof solution A contains 0.1 mg of copper.

Solution B is prepared as follows: 10 cmstandard solution And copper is placed in a volumetric flask with a capacity of 100 cm, flow 10 cmof hydrochloric acid, cool, dilute to the mark with water and mix.

1 cmof a solution contains 0.01 mg of copper.

Solution; prepared as follows: 1 cmof the standard solution And the copper is placed in a volumetric flask with a capacity of 100 cm, flow 10 cmof hydrochloric acid of 25 cmof water, cool, dilute to the mark with water and mix.

1 cmof the solution contains 0.001 mg of copper.

The solution used freshly.

Standard solutions of cadmium.

Solution A, prepared as follows: the weight of cadmium weight 0,100 g dissolved in 10 cmof nitric acid, diluted 1:1, and evaporated to dryness. Pour 2 cmof hydrochloric acid, and evaporated to a moist residue. Pour 50 cmof hydrochloric acid, 200 cmof water, cooled, quantitatively transferred to a volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.

1 cmof solution A contains 0.1 mg of cadmium.

Solution B is prepared as follows: 10 cmstandard solution While cadmium is placed in a volumetric flask with a capacity of 100 cm, flow 10 cmof hydrochloric acid, cool, dilute to the mark with water and mix.

1 cmof a solution contains 0.01 mg of cadmium.

Solution; prepared as follows: 1 cmof a standard solution While cadmium is placed in a volumetric flask with a capacity of 100 cm, flow 10 cmof hydrochloric acid of 25 cmof water, cool, dilute to the mark with water and mix.

1 cmof the solution contains 0.001 mg of cadmium.

The solution used freshly.

Standard solutions of zinc

Solution A, prepared as follows: the weight of zinc weight 0,100 g dissolved in 50 cmof hydrochloric acid, pour 200cmof water, cooled, quantitatively transferred to a volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.

1 cmof solution A contains 0.1 mg of zinc.

Solution B is prepared as follows: 10 cmstandard solution And zinc is placed in a volumetric flask with a capacity of 100 cm, flow 10 cmof hydrochloric acid, cool, dilute to the mark with water and mix. The solution used freshly.

1 cmof the solution contains 0.01 mg of zinc.

Calibration solutions of copper, cadmium and zinc; prepared as follows: batches of thallium weight of 1,000 or 5,000 g (see table.1), before the decomposition of their acid-metered micropipette standard solutions of copper, cadmium and zinc and lead further their training, as specified in sec. 3. The dilution volume of the sample solution with additives and concentrations of additives in them are shown in table.1.

Table 1

The background electrolyte. In 1 DMof the solution contains 100 g of ammonium chloride and 100 cmof ammonia.

In the case of polarographically on the oscilloscope polarography 1 DMbackground electrolyte must contain 20 cmof gelatin solution. The background electrolyte is stable for 7 days.

Live-, -dialogically (hloreksa).

Methyl isobutyl ketone.

Gelatin food according to GOST 11293, solution 20 g/l, freshly prepared.

(Changed edition, Rev. N 2, 3).

3. ANALYSIS

3.1. In a conical flask with a capacity of 100 cmis placed a portion of the thallium weighing 1,000 g (with mass fraction of thallium 99,98−99,99%) or 5,000 g (with mass fraction of thallium 99,999-of 99.9995%), pour nitric acid, diluted 1:1 (the hitch weight 1,000−2,000 g 4−6 cm, the hitch weight 5,000 g 8 cminto the flask with the control sample respectively 4, 6, 8 cm), cover with a watch glass and dissolved under heating. Glass is removed and the sample evaporated to a moist residue. Cooled and poured to the sample containing weighed 1,000 g — 2 cm, samples containing sample 2,000 g and 5,000 g respectively, 5 and 10 cmof hydrochloric acid and cautiously evaporated to complete the removal of nitrogen oxides.

To the residue is poured a solution of bromatological acid (HBr)=4 mol/DM(to the sample with a hitch weight 1,000−2,000 g 10−15 cm, to the sample with a hitch weight of 5,000 g or 20 cm), respectively, 0.5 and 1 or 3 cmof bromine, cover with a watch glass and leave until complete dissolution of thallium in a warm place with occasional stirring.

The sample solution (releasing a pair of bromine) after cooling, transferred to a separatory funnel with a capacity of 120−150 cm, go to the solutions containing weighed samples of 1,000 g, is 20 cm, 2,000 g and 30 cm, for a solution containing a sample of 5,000 g, — 60 cmhloreksa until warm to touch, they pre-flask in which to carry out the decomposition, and extracted thallium with slow shaking for 2 min. After phase separation, the organic layer is discarded, the separating funnel is poured in accordance with the weighed samples 10; 20 or 30 cmhloreksa, 1−2 drops of bromine and the extraction of thallium repeat. After resetting the second portion of hloreksa extraction of thallium repeat two more times.

The aqueous layer, after reset hloreksa, is poured through the pipe into another separatory funnel, add 1−2 drops of bromine, 10 cmhloreksa, shaken for 2 min. After careful separation of the hloreksa the aqueous layer is drained through the neck into the beaker with a capacity of 50 cm, evaporated to a volume of 3−4 cm, pour 1 cmof perchloric acid and evaporated to release vapors last, pour 1 cmof nitric acid and continue to evaporate to almost complete removal of perchloric acid.

In the presence of thallium tellurium, set in advance, thallium is extracted as shown to transfer the water layer into another funnel, but instead hloreksa add 15 cmof methyl isobutyl ketone (bromine is not added) and extracted tellurium, indium and thallium residues during 1 min. the Aqueous layer was placed in a beaker with a capacity of 50 cmand then do as above.

To the residue after evaporation of the acid poured 5−10 or 20 cm, background electrolyte (see table 1), is added for every 5 cmto about 50 mg of sodium sulfite, stirred and spend polarography of copper, cadmium and zinc, respectively, in the peak potentials of 0.52 minus minus minus 0.82 and 1.4 V relative to a saturated calomel electrode. In similar conditions polarographic solution of the control sample and calibration solutions. The value of the wave height in the reference experiment is subtracted from the height of the wave samples and process the results of the analysis.

The oscillographic polarograph used in the analysis of copper, cadmium and zinc in thallium with mass fraction of its 99,98−99,99%.

(Changed edition, Rev. N 2, 3).

4. PROCESSING OF THE RESULTS

4.1. The mass percent of copper, cadmium, or zinc () in percent is calculated by the formula

,

where  — height of a wave of copper (cadmium or zinc) in polarography of the sample solution, mm;

 — the height of a wave of copper (cadmium or zinc) in polarography of the sample solution with a standard additive, mm;

 — the volume of the sample solution, cm;

 — mass concentration of standard addition of copper (cadmium or zinc) in calibration solution, mg/DM;

the weight of thallium,

(Changed edition, Rev. N 2, 3)

.

4.2. The absolute values of the differences between the results of two parallel measurements (rate of convergence) and the results of the two tests (index of reproducibility) with confidence probability of 0.95 does not exceed values of allowable differences specified in table.2.

Table 2

(Changed edition, Rev. N 3).