GOST 12645.10-86

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  ГОСТ 12645.10-86

GOST 12645.10−86 indium. Method for the determination of sulphur (Change No. 1)

GOST 12645.10−86*

Group B59

STATE STANDARD OF THE USSR

INDIUM

Method for the determination of sulfur

Indium.
Method for determination of sulphur

AXTU 1709

Date of introduction 1988−01−01

Resolution of the USSR State Committee for standards from 23.10.86 N 3188 date of introduction is established 01.01.88

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

Change N 1 GOST 12645.10−86 adopted by the Interstate Council for standardization, Metrology and certification by correspondence 15.04.94 (report of the Technical Secretariat N 2)

The adoption voted:

* REISSUE (March 1998) with amendment No. 1, approved in June 1996 (IUS 9−96)

1a. Scope

This standard sets the polarographic method for the determination of sulfur (with sulfur mass fraction of from 5·10to 1·10%) in India brand Ying 000.

The method is based on the recovery of sulphur compounds to hydrogen sulphide, Stripping and absorption solution of alkali in the presence of hydroxylamine and Trilon B and polarography solution containing sulfide ions.

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 22306−77 with additions.

1.1.1. The mass percent of each element in India define in two parallel batches.

1.1.2. The control accuracy of the analysis carried out by the method of variation of batches or by the method of additions. The control accuracy of the analysis is carried out simultaneously with the analysis of samples when changing reagents, instruments, and after a long break.

1.1.2.1. When accuracy control method of varying the batches analysis is carried out this method from batches 1 and 2 g India. The result of the analysis is considered correct if the difference between the test results obtained from different batches, does not exceed the permissible differences given in the table.

1.1.2.2. The control accuracy by the method of additions is carried out in accordance with GOST 25086−87.

As the additive use sulphuric acid solutions containing 0.1 and 1 µg/cmsulfur, prepared with bidistilled water in a day of application. The procedure is performed as specified in sec. 5.

For samples with a sulfur mass fraction of 5·10% or more of the additive should be not less than mass fraction of sulfur in the sample and not more than twice the mass fraction of sulfur in the sample. Mass fraction of sulfur in the sample with the additive should be not less than 1·10% and not more than 3·10%.

The amount of additives is determined by difference , where and  — the results of the analysis of the sample and the sample with the additive , calculated as the arithmetic mean of the two determinations, the differences between them should not exceed the permissible value specified in the standard.

The result of the analysis is considered correct if the value found additives different from the estimated value supplements the value of not more than 0.71·, where and  — the permissible discrepancy of the results of the analysis of sulfur in the sample and in the sample with up to

the additive .

1.1.1−1.1.2.2. (Changed edition, Rev. N 1).

2. SAFETY REQUIREMENTS

2.1. Safety requirements — according to GOST 12645.8−82 with additions.

2.1.1. Indium (oxide) according to GOST 12.1.005−88 is a substance of third class risk and has a maximum allowable concentration (Mac) of 4 mg/m. Indium causes pain in the joints, bones, tooth decay, nervous and gastrointestinal disorders, pain in area of heart and General weakness.

Control over the content of indium in air of working zone shall be conducted according to methods developed in accordance with GOST 12.1.016−79 and approved by the health authorities. Periodicity of control is established in accordance with GOST 12.1.005−88.

(Changed edition, Rev. N 1).

2.1.2. The analyses with the use of mercury is carried out in accordance with the sanitary rules of design, equipment, operation, and maintenance of production and laboratory premises, intended for work with mercury, its compounds and instruments with filling of mercury adopted by the USSR Ministry of health.

2.1.3. When you use gases in cylinders must comply with the safety requirements in accordance with the «Rules for design and safe operation of vessels working under pressure», approved by Gosgortekhnadzor of the USSR.

2.1.4. Fire safety laboratory spaces shall be provided in accordance with the requirements of GOST 12.1.004−91. Space chemistry lab should be equipped with fire extinguishing means (a fire extinguisher with carbon dioxide, asbestos sheet, sand).

3. APPARATUS, MATERIALS AND REAGENTS

Polarograph type AC-PPT-1 or the universal polarograph PU-1.

Plant for recovery of sulphur compounds, and distilling off the hydrogen sulfide. (You may use back of the refrigerator and the receiver of any design that ensures the full absorption of sulfide ions).

The unit according to GOST 14919−83.

The external cell with an anode compartment (anodic compartment above the mercury is filled daily with saturated solution of potassium chloride).

Argon according to GOST 10157−79.

Cup quartz GOST 19908−90 with a capacity of 50 cm.

Hydrochloric acid by the GOST 3118−77.

Nitric acid GOST 4461−77 distilled.

Sulfuric acid GOST 4204−77, diluted 1:6, and a solution of 0.05 mol/DM, made with standard-titre.

Itestosterone acid according to GOST 4200−77.

Potassium iodide according to GOST 4232−74.

Potassium hydroxide according to GOST 24363−80.

Potassium chloride according to GOST 4234−77, recrystallized, saturated solution.

Sodium hydroxide according to GOST 4328−77, solutions of 100 and 250 g/DM.

Copper dichloride 2-water according to GOST 4167−74.

Sodium sulfide according to GOST 2053−77.

Sodium posterolaterally according to GOST 200−76.

Potassium posterolaterally.

Hydroxylamine hydrochloride according to GOST 5456−79, a solution of 69.5 g of hydroxylamine hydrochloride was diluted with bidistilled water up to 1 DM.

Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid 2-water (Trilon B) according to GOST 10652−73.

Mercury GOST 4658−73.

Pyrogallol And a solution of 250 g/DMin the solution 250 g/DMsodium hydroxide.

Distilled water GOST 6709−72, is further distilled in a quartz apparatus with addition of potassium permanganate.

Potassium permanganate according to GOST 20490−75.

The alkaline mixture is aged not less than 2 days; in a volumetric flask with a capacity of 1 DMflow 600 cmsvejeprokipachenna and chilled double-distilled water was added 112 g of potassium hydroxide, stirred until dissolved, the solution was cooled and portions added to it 100 g Trilon B with stirring and diluted to 1 DMsvejeprokipachenna double-distilled water, mix and close the glass stopper.

Polarographic background: 120cmalkaline mixture is placed in a conical flask with a glass stopper with a capacity of 250 cm, flow 25 cmof a solution of hydroxylamine hydrochloride, 100 cmdouble-distilled water and stirred. The background can be used for 3 days.

Recovery the mixture is prepared in two ways:

Method 1.

In the reaction flask is poured 730 cmof hydrochloric acid (1,2:1), added 444 g of potassium iodide, 150 g of sodium phosphonoacetate (or 173 g of potassium phosphonoacetate), 250 mg of dichloride of copper, mix, set opposite the fridge and boil for 5−6 h with purging of argon at a rate of 20−25 bubbles in 10 s. Argon pre-cleaned by passing through three flask Drexel with a solution of pyrogallol 250 /DM* solution of potassium hydroxide 250 g/DM. During cooling from the recovery of the mixture should stand a variety of temperatures (the absence of sediment indicate a lack of hydrochloric acid concentration). The recovery mixture was decanted from the precipitate of salts and store in a flask with a glass stopper in a darkened box.
________________
* Consistent with the original. — Note the manufacturer’s database.

Method 2.

Mix 300 cmof salt, 500 cmitestosterone acids, 150 g of sodium phosphonoacetate (or 173 g of potassium phosphonoacetate), 250 mg of dichloride of copper, pour 200 cmdouble-distilled water and stirred. Purification of the mixture from sulfur produced as described above.

Standard solutions of sulphate sulphur

Solution a: 6,25 cmof sulfuric acid solution 0.05 mol/DMare placed in a volumetric flask with a capacity of 100 cm, made up to the mark svejeprokipachenna double-distilled water, and stirred.

1 cmof the solution contains 100 micrograms of sulfur.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, svejeprokipachenna bring to mark with bidistilled water and stirred.

1 cmof a solution containing 10 micrograms of sulfur.

Solution: 10 cmof solution B is placed in a volumetric flask with a capacity of 100 cm, made up to the mark svejeprokipachenna double-distilled water, and stirred.

1 cmof the solution contains 1 µg of sulfur.

Solution: 10 cmsolution is placed in a volumetric flask with a capacity of 100 cm, made up to the mark svejeprokipachenna double-distilled water, and stirred.

1 cmof the solutioncontains 0.1 µg of sulfur.

Solutions B, C, prepared on the day of use.

Standard solutions of sulfide sulfur

Solution G: 75 mg of the crystal of sodium sulfide was placed in a volumetric flask with a capacity of 100 cm, pour the polarographic background to the mark and mix to dissolve the salt.

1 cmsolution G contains 100 µg of sulfur.

Solution D: 10 cmsolution G was placed in a volumetric flask with a capacity of 100 cm, made up to the mark polarographic background and stirred.

1 cmof a solution D containing 10 micrograms of sulfur.

(Changed edition, Rev. N 1).

4. PREPARATION FOR ASSAY

4.1. Assembly installation

Collect installation for the recovery and distillation of sulfur in accordance with the drawing. Then in the flask Drexel with a capacity of 200 cm1−3 flooded by 150 cmof the alkaline solution of pyrogallol, in a flask with a capacity of 200 cmwith dibattista 4 — a solution of sodium hydroxide 250 g/DM, in a bottle 11 — distilled water, 5 and 10 of the safety flask. The receiver length 250 mm 9 pour 5 cmof the background electrolyte. Fitting pressure gauge gas cylinder with argon is connected to the flask 1 rubber hose, pre-boiled in sodium hydroxide solution 100 g/DMand washed with distilled water. Flasks 1−5, 10 and 11, the reaction flask 7 and the receiver 9 connect the vinyl chloride hoses. Reverse refrigerator 8 is connected to a water tap flexible rubber hose.

4.2. Check tightness of installation

In the reaction flask 7 pour 150 cmpre-treated recovery of the mixture, and the receiver 9 — 5 cmpolarographic background. Through the installation of flow flow of argon at a rate of 15−20 bubbles 10, previously missing cold water through a reverse refrigerator. About the tightness of the installation is judged by matching the speed of passage of bubbles of argon in the flask Drexel 1 and receiver 9. If sections are leaking, their proshlifovat fine powder abrasive.

Then, through the socket tube of the reaction flask by pipette administered 0.2 cmstandard solution B sulphate sulphur. The sulfide was removed within 35−40 min from power on electric.

The receiver of sulfur is disconnected from the installation, the content of the receiver poured into the cell and register polarogram solution under cathodic polarization from minus 0.45 to minus 0.9 In (relative to the saturated calomel electrode).

The peak height of sulfur at polarogram solution in the receiver is compared with the peak height of standard solution of sulfide sulfur D (to obtain this solution, 0.2 cmof a standard solution of sulfide sulfur D dilute polarographic background to 5 cm).

Installation for recovery of the sulfur and Stripping of hydrogen sulfide

The difference between the heights of peaks of both solutions should not exceed 10% Rel. Otherwise, check the tightness and repeat the definition.

4.3. The control experience

The reaction flask is 7, the inverse of the refrigerator 8 and the receiver for detecting hydrogen sulfide gas 9are washed with hydrochloric acid and svejeprokipachenna double-distilled water, pour 150 cmrecovery mixture. Fixed in the neck of the reaction flask in the refrigerator. In the receiver pour 5 cmof the polarographic background, inserted into the receiver cone of the vapor tube, connect the tube of the receiver with a safety flask 10 and is passed through the installation of argon at a speed of 30−35 bubbles in 10 s. Connect refrigerator to the water supply and, 5−10 min later, turn the hot plate 6. From the moment of boiling Stripping continued for 30 min.

After distilling off the hydrogen sulfide, the receiver is disconnected from the installation, the contents poured into the cell and remove polarogram solution, as specified in clause 4.2.

In similar conditions hold polarographically solutions obtained by reduction of sulphate sulphur, and calculates the correction control of the experience by the formula

,

where is the mass of sulfur in the standard sulphate solution comparison, mcg;

the peak height of sulfur in a control experiment, mm.

 — the height of the peak in sulfur solution comparison, mm.

The sulfur content in a control experiment should be less than 0.05 mg. If the test experience more — experience in the Stripping of sulfur from the recovery portion of the mixture is repeated, after washing the inlet of the receiver and the receiver svejeprokipachenna distilled water. The value of the reference experience check every day before starting work and after each transition from the distillation of large quantities of sulfur to the Stripping of small amounts of sulfur.

Portion of the recovery of a mixture of 150 cmcan be used for the analysis of 6−8 samples from India (6−8 g).

5. ANALYSIS

After the control experience washed outlet of receiver 9 boiled distilled water without disconnecting the current of argon. The reaction flask 7 is cooled, the water flowing through the coil 12, and is poured into the receiver is 9 5 cmthe polarographic background. Then the reaction flask was placed 1,000 g of finely chopped India (pre-treated with nitric acid (1:6) 30 C and acetone at room temperature in a quartz Cup), attach the back of the refrigerator 8, the receiver 9 with a safety flask 10comprise a hot plate 6 and displace the oxygen with argon from the system within 30 minutes you experience a release of hydrogen, obtained by dissolving indium in replacement mixture. The velocity through the receiver 20 of bubbles in 10 s. Current of argon do not stop until complete dissolution of indium in the recovery of the mixture. After dissolution of the indium solution is heated to boiling and continue the Stripping of sulfur for 30 min.

The receiver of sulfur is disconnected from the installation, the contents poured into the electrolyser and conduct polarographically solutions as stated in point 4.2.

Washed the nozzle and receiver twice boiled distilled water, cooled the reaction flask in the receiver pour 5 cmof the polarographic background, enter 0.5−5.0 cmstandard solution Into0.5−1.0 cmof a solution of sulphur In sulphate (depending on the sulfur content in the sample) and carry out the Stripping of sulfur in the form of hydrogen sulphide, as described above.

Disconnect the receiver from the setup and hold polarographically the resulting solution comparison as specified in clause 4.2.

(Changed edition, Rev. N 1).

6. PROCESSING OF THE RESULTS

6.1. Mass fraction of sulfur () in percent is calculated by the formula

,

where is the mass of sulfur in the solution comparison, the mcg;

the peak height of sulfur of the sample solution, mm;

the peak height of sulfur, obtained in a control experiment, mm.

the peak height of sulfur solution comparison, mm;

 — the weight of the portion of the sample,

The result of the analysis taking the arithmetic average of the results of two parallel measurements.

(Changed edition, Rev. N 1).

6.2. Allowable absolute difference between the results of two parallel determinations and the results of the two analyses at a confidence level of 0.95, should not exceed the values given in the table.

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