GOST 13637.5-93

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  ГОСТ 13637.5-93

GOST 13637.5−93 Gallium. Method for determination of tin

GOST 13637.5−93

Group B59

INTERSTATE STANDARD

GALLIUM

Method for determination of tin

Gallium.
Method for the determination of tin

AXTU 1709

Date of introduction 1995−01−01

Preface

1. DEVELOPED by the Interstate technical Committee 104 «of the Semiconductor and rare metals products. Especially pure metals», State Institute of rare metals (Giredmet)

INTRODUCED by Gosstandart of Russia

2. ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 4−93 of 19 October 1993)

The adoption voted:

3. Resolution of the Committee of the Russian Federation for standardization, Metrology and certification from 02.06.94 N 160 inter-state standard GOST 13637.5−93 introduced directly as state standard of the Russian Federation from 01.01.95

4. REPLACE GOST 13637.5−77

INFORMATION DATA

REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard specifies a method for Stripping alternating-current voltammetry for the determination of tin in Gaul (with mass fraction of tin from 3·10to 1·10%).

The method is based on coprecipitation of compounds of tin (IV) phosphate of beryllium in ammonium solution ethylenediaminetetraacetic acid, dissolving the precipitate in hydrochloric acid solution and determination of tin by the method of inversion, alternating-current voltammetry in the presence of gelatin.

1. GENERAL REQUIREMENTS

General requirements for method of analysis and security requirements — according to GOST 13637.0.

2. APPARATUS, REAGENTS AND SOLUTIONS

Polarograph PPT-1, PU-1 or similar with a stationary mercury electrode and electrolytic cell polarography with the outer anode compartment. In the anode compartment is filled, metallic mercury and polarographic background.

Laboratory scales of the 1st class according to GOST 24104*.
_______________
* On the territory of the Russian Federation GOST 24104−2001. — Note the manufacturer’s database.

The roughing pump brand VM-461-M or similar.

Tile laboratory electric power of 400 watts.

Volumetric flasks with a capacity of 50, 100, 200 and 1000 cm.

Measuring cylinders with capacities of 10, 25 and 50 cm.

Pipettes with graduations at 0.1; 0.2 and 1 cm.

Buchner funnel with a diameter of 100 mm.

Quartz test tube with the outlet of the suction capacity of 40 cm.

The chemical glasses with a capacity of 2000 cm, 250 cm.

Watch-glasses with a diameter of 90 mm.

Filter FKP-32-ПОР40.

Sticks to glass.

Bunsen flask with a capacity of 500 cm.

Dropper with a capacity of 50 cm.

Hydrochloric acid of high purity according to GOST 14261, distilled and the solutions with concentration of 3 and 1 mol/DM.

Nitric acid of high purity according to GOST 11125.

Orthophosphoric acid according to GOST 6552, diluted 3:1.

The aqueous ammonia of high purity according to GOST 24147 and diluted 1:1.

Mercury brands r0 according to GOST 4658.

Polarographic background — hydrochloric acid solution with a concentration of 3 mol/DM.

Aqua Regia a mixture of concentrated nitric and hydrochloric acids in a volume ratio of 1:3.

Potassium permanganate according to GOST 20490.

The technical rectified ethyl alcohol according to GOST 18300 is used when charging the electrodes in accordance with the instructions for polarography.

Potassium hydroxide according to GOST 24363.

Zinc, granulated.

Zinc chloride solution with a mass concentration of 0.5 mol/DM. 3,2690 g of granulated zinc is placed in a beaker with a capacity of 300 cm, 20−30 cm, moistened withwater and poured in small portions of 25 cmof a solution of distilled hydrochloric acid. The solution is evaporated to wet salts, salt dissolved in water, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water.

Bidistilled water: distilled water is poured into the flask, quartz distillation apparatus with a capacity of 2 DM, is poured 1 g of potassium hydroxide and potassium permanganate to intense staining. The solution was heated. Collect the middle fraction of the distillate component of the taken volume of distilled water, the first and third fractions discarded.

Salt is the disodium Ethylenediamine-, , , -tetraoxane acid, 2-water (Trilon B) according to GOST 10652.

A solution of ethylenediaminetetraacetic acid: 500 g Trilon B pour 300 cmof distilled water in a beaker with a capacity of 2 DMand then while stirring with a glass rod, add concentrated ammonia solution until complete dissolution. If the solution is turbid, it is filtered through a thick folded filter in a glass with a capacity of 2 DM. This is followed by a neutralization with a solution of distilled hydrochloric acid until then, until put in a glass piece of blue indicator paper Congo red red-brown color (pH 3). Emitted while sludge ethylenediaminetetraacetic acid is filtered through a paper filter on a Buechner funnel and washed 5−7 times with cold distilled water.

The washed pellet was transferred to a beaker and dissolved in ammonia (1:1). The molar concentration of a solution of ethylenediaminetetraacetic acid set by GOST 10398 solution of zinc salt.

Beryllium hydroxide.

A solution of beryllium: 36 g hydroxide of beryllium is dissolved in the hydrochloric acid concentration of 3 mol/DM. The solution was transferred to a volumetric flask with a capacity of 500 cmand was adjusted to the mark with hydrochloric acid of concentration 1 mol/DM.

Gelatin food according to GOST 11293, an aqueous solution concentration of 5 mg/cm.

Methyl orange aqueous solution with a concentration of 1 mg/cm.

Phenolphthalein, alcohol solution of concentration 1 mg/cm.

Eriochrome black.

Tin GOST 860.

A solution of tin (main): 1 g of tin are dissolved in 100 cmdistilled hydrochloric acid and 5 cmof nitric acid when heated. After the dissolution and disappearance of brown fumes of oxides of nitrogen the solution was cooled, transferred into a measuring flask with volume capacity of 1000 cmand bring to mark polarographic background.

1 cmof the solution contains 1 mg of tin (IV).

A solution of tin (operating): 10 cmbasic solution of tin is poured into a measuring flask with a capacity of 100 cm, made up of the polarographic background to the mark and mix.

1 cmof the solution contains 100 micrograms of tin (IV).

More dilute working solutions of tin is prepared by successive dilution of the polarographic background in a volume ratio 1:9 on the day of use.

3. ANALYSIS

3.1. Dissolution samples

A portion of gallium by mass of 2 g was dissolved with heating in 25 cmof distilled mixture of hydrochloric and nitric acids, taken in the ratio of 5:1, in a glass with a capacity of 300 cmunder the watch glass. After dissolution of the sample remove the glass, wash the glass and walls of beaker with distilled water, then the solution is evaporated to approximately 15 cm. The side of the Cup is washed two times with distilled water in portions of 15−20 cm, each time uparima the contents of the Cup to approximately 15 cm. After complete removal of nitrogen oxides in the glass is poured 60−80 cmof distilled water, 2 cmof phosphoric acid, 30/Msolution of ethylenediaminetetraacetic acid (where M is the molar concentration of this solution, mol/DM), 2 drops of a solution of methylorange and aqueous ammonia solution until the yellow colour of methylorange. The solution is heated to boiling. Add hydrochloric acid dropwise until slightly pink staining methylorange. Then add 0.3 cmof a solution of beryllium, 2 drops of solution of phenolphthalein and ammonia water solution rapidly in one portion. The required amount of ammonia to neutralize the solution until the red color of phenolphthalein is set in a parallel experience with the same amount of ethylenediaminetetraacetic acid. Then the solution was added 2 cmof ammonia solution and hot water to a total volume of 150 cm. The solution after 1−2 min was stirred with a glass rod and leave to coagulate the precipitate. The hot solution is sucked off through the sintered filter PCF in a Bunsen flask, and the residue on the filter is washed 10 times with hot double-distilled

water.

3.2. Polarographically

The washed precipitate of phosphate of beryllium dissolved in the porous filter 15 cm(in two steps), distilled with hydrochloric acid. The solution is aspirated into a quartz tube process, the filter was washed with 12 cmdouble-distilled water. The washing water is also aspirated into a test tube. To the solution in a test tube add two drops of gelatin solution. The solution was transferred to measuring cylinder and adjusted with bidistilled water up to 25 cm. Inversion of the resulting solution voltamperometry register in the following conditions: the size of the stationary mercury drop corresponds to 20 divisions of the clock indicator; the potential accumulation minus 0,60 V; duration of accumulation with stirring 3 min, the peak Capacity of tin of about minus 0,49 V. the Voltammogram of each solution is removed three times.

3.3. Transcript of inversion voltammograms

The peak height is measured vertically, is drawn through the top of the peak to the intersection with a tangent connecting the bases of the branches peak. Each of the peak heights should not vary from the arithmetic average of the peak height by more than 0.2 . If the height of the first peak differs from the average by more than 0.2 , the height of the first peak is not considered.

Mass fraction of tin in the sample is determined by method of additions. The addition of the diluted working solution of tin not exceeding 1 cmis introduced into the entire volume polarographic solution. The solution with the addition of polarographic the same way as the analyzed solution.

Supplement should to increase the mass of tin in polarographically solution (and peak height) by 2−3 times, if the tin content in the sample calculated according to claim 4.1, not less than 3·10%.

If less than 3·10%, the additive should be 0.05 µg of tin. When more than 3·10%, the additive should be less than 0.1 µg and not more than 2 mg.

With each series of samples is carried out two test experience.

4. PROCESSING OF THE RESULTS

4.1. Mass fraction of tin () in percent is calculated by the formula

,

where  — weight of tin in addition, mcg,

 — arithmetic average peak height prerogrative of the sample solution minus the arithmetic mean values of the peak height of the tin in a control experiment, mm

the weight of gallium, g,

 — arithmetic average peak height of the sample solution with the additive minus the arithmetic mean values of the peak height of the tin in a control experiment, mm

 — volume polarographic solution sample of sample, cm,

 — volume Supplement, sm.

The average of heights of peaks of tin () obtained in control experiments, um, shall not exceed the values

.

4.2. The result of the analysis taking the arithmetic average of the two results of parallel measurements carried out from separate batches.

The allowable discrepancy of the two results of parallel measurements and the two results of the analysis (the difference between larger and smaller) with confidence probability of 0.95 is given in the table.

Permitted discrepancies for the intermediate mass fraction of tin calculated using linear interpolation.

4.3. Control of the correctness analysis is carried out by additives according to GOST 25086.