GOST 12645.2-77

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  ГОСТ 12645.2-77

GOST 12645.2−77 indium. Spectral method for determination of mercury and cadmium (with Amendments No. 1, 2, 3)

GOST 12645.2−77

Group B59

STATE STANDARD OF THE USSR

INDIUM

Spectral method for determination of mercury and cadmium

Indium. Spectral method for determination of mercury and cadmium

AXTU 1709

Date of introduction 1978−07−01

INFORMATION DATA

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

DEVELOPERS

A. P. Sychev, L. K. Larina (supervisor), M. G. Saun (supervisor), V. N. Makarceva, N. With. References: E. V. Lisitsyn, N. Romanenko, V. A. Kolesnikov

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 08.07.77 N 1715

Change No. 3 adopted by the Interstate Council for standardization, Metrology and certification 15.03.94 (report of the Technical Secretariat N 1)

The adoption voted:

3. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

4. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)

5. REPRINT (January 1998) with Amendments No. 1, 2, 3, approved in February 1983, December 1987-June 1996 (IUS 5−83, 3−88, 9−96)


This standard establishes a spectral method for the determination of mercury and cadmium in India for the mass concentration of mercury from 1·10to 8·10%, cadmium from 1·10to 8·10%.

The determination of mercury and cadmium in India produced by the method of «three standards» with the evaporation of mercury and cadmium from the crater of the carbon electrode in the arc AC.

(Changed edition, Rev. N 1, 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis and security requirements — according to GOST and GOST 12645.0 22306.

(Changed edition, Rev. N 2).

2. APPARATUS, REAGENTS AND MATERIALS

The quartz spectrograph medium dispersion of any type or spectrograph STE-1 being the illumination system of the slit.

Arc generator of alternating current.

Microphotometer designed to measure pucherani spectral lines.

Libra torsion bar type W with a weighing error of no more than 0.001 g.

Analytical scale with a weighing error of no more than 0,0002 g.

Electrodes, carbon, 6 mm in diameter with a crater size 4x6 mm.

Spectrographic plates of the type II or type SFC-02, NT-2SV, SFC-03, PFS-04.

Standard samples developed in accordance with GOST 8.315*.
______________
* On the territory of the Russian Federation GOST 8.315−97. — Note the manufacturer’s database.

Note. Allowed the use of devices with photovoltaic spectra and other spectral instruments, other reagents and materials, providing the accuracy that rivals regulated in this standard.

(Changed edition, Rev. N 1, 2, 3).

3. ANALYSIS

Determination of mercury and cadmium is carried out on the spectrograph of STE-1 with a being system of the slit illumination via the three-step attenuator. The slot width of 0.015 mm. the Weight of the portion of the sample or the reference sample (200 mg) in the form of metal pieces placed in a hole in the bottom carbon electrode depth of 6 mm, a diameter of 4 mm and thoroughly compacted with a kick ball made of organic glass. The upper electrode is coal, sharpened to a truncated cone with the diameter of the via pad 2 mm; between the electrodes is ignited, the alternating current arc power of 10 A. the exposure Time of 70 s, the distance between the electrodes is 3 mm.

Spectra of the samples photographed for six samples comparison — three times on a single photographic plate. In the determination of mercury in the range of mass fraction from 1·10to 8·10spectra allowed to photograph on the quartz spectrograph of the ISP-30 for 30 s, respecting all the above conditions of the analysis.

(Changed edition, Rev. N 2, 3).

4. PROCESSING OF THE RESULTS

4.1. In the spectrogram, using microphotometry measure the blackening of analytical lines of mercury Hg 253,65 nm, cadmium, Cd 228,8 nm and the surrounding background. In the determination of mercury at the spectrograph STE-1 calibration graphs constructed in the coordinates , ,

where is the intensity of the mercury line;

 — the intensity of the background;

 — mass fraction of mercury in the standard samples, %.

The construction of the characteristic curve of photographic plates and the calculation of the intensity — according to GOST 24977.1.

When determining the mass fraction of cadmium and mercury (more than 1·10%) the calibration graphs are built in coordinates , where ,  — mass fraction of cadmium or mercury in the standard samples.

For the results analysis be the arithmetic mean of results of two parallel measurements obtained on the same photographic plate of three spectrograms each.

The difference between the smaller and larger of the two results of parallel measurements with a confidence probability of 0.95 does not exceed the value of permissible differences calculated by the formulae:

 — mass fraction of mercury from 1·10to 1·10%;

 — mass fraction of mercury and cadmium from 1·10to 8·10%,

where  — the average of the two mapped results of parallel measurements.

The difference between the smaller and larger of the two results of the analysis of the same samples with a confidence level of 0.95 does not exceed the value of permissible differences calculated by the formulae:

 — mass fraction of mercury from 1·10to 1·10%;

 — mass fraction of mercury and cadmium from 1·10to 8·10%,

where  — the average of the two matched analyses.

(Changed edition, Rev. N 1, 2, 3).

4.2. (Deleted, Rev. N 1).