GOST 26880.2-86

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  ГОСТ 26880.2-86

GOST 26880.2−86 (ST SEV 5510−86) Lead. Methods for determination of sodium and potassium (with Amendments No. 1, 2)

GOST 26880.2−86
(ST CMEA 5510−86)*
________________________
* The designation of the standard.
Changed the wording, Rev. N 1

Group B59

STATE STANDARD OF THE USSR

LEAD

Methods for determination of sodium and potassium

Lead. Methods of sodium and potassium determination

AXTU 1709

Valid from 01.01.87
before 01.01.92*
__________________________
* Limit of validity
removed by the resolution of Gosstandart of the USSR
from 17.07.91 N 1261 (IUS N 10, 1991). -
Note the manufacturer’s database.

DEVELOPED by the Ministry of nonferrous metallurgy of the USSR

PERFORMERS

G. I. Ivanov, R. D. Kogan, K. L. Larina, N. N. Averina, T. I. Trishechkin

INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

Member Of The Board Of A. P. Snurnikov

APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards, dated 25 April 1986 N 1073

REPLACE GOST 20580.9−80*, GOST 20580.12−80
________________
*Probably, the error of the original. Should read 20580.9 GOST-78.- Note the manufacturer’s database.


MADE: the Change in N 1, approved and put into effect by the Decree of the USSR State Committee for standards from 24.04.87 N 1399 from 01.01.88, Change No. 2, approved and put into effect by the Decree of Committee of standardization and Metrology of the USSR from 17.07.91 N 1261 with 01.03.92

Change N 1, 2 made by the manufacturer of the database in the text IUS N 2, 1987, ICS # 10, 1991


This standard establishes the atomic absorption and atomic emission methods for the determination of sodium and potassium in the metallic lead with a mass fraction of sodium from 5·10to 5·10% potassium and from 5·10to 4·10%.

The method is based on measuring absorption or emission of the resonance lines of sodium 589,0 and 589,6 nm and potassium at 766,5 nm introduction analyzed and solutions comparison of air-acetylene or air-butane-propane flame. Samples of lead previously transferred to the solution with decomposition in dilute nitric acid.

The standard fully complies ST SEV 5510−86.

(Changed edition, Rev. N 1, 2).

1. GENERAL REQUIREMENTS

1.1. General requirements — according to GOST 26880.1−86.

2. SAFETY REQUIREMENTS

2.1. Safety requirements — according to GOST 26880.1−86.

3. APPARATUS, MATERIALS, REAGENTS AND SOLUTIONS

Spectrophotometer atomic absorption option emission of work and radiation sources for sodium and potassium or a fiery photometer.

Acid, nitric acid high purity according to GOST 11125−84 brand OS.H. 18−4 OS.H. 21−5 and the solutions are 1:3 and 1:6.

Sodium nitrate according to GOST 4168−79 with a mass fraction of potassium not more than 0.0004%, the solution 100 g/lof sodium. To check the purity of sodium nitrate, a solution of 100 g/DMsodium, then in a volumetric flask with a capacity of 50 cmcarry 2.5 cmof the prepared solution, adjusted to the mark with water and mix. Measure the emission or absorption of this solution. If it is about 20% of the lower concentration (0.1 µg/cm) solution comparison (which corresponds to the mass fraction of potassium 0,0004%), this salt is suitable for use.

Sodium chloride according to GOST 4233−77.

A standard solution of sodium.

2,5421 g pre-dried in a drying Cabinet at a temperature of (100±5) °C for 1 h and cooled in a desiccator sodium chloride is dissolved in water, transferred to a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.

1 cmof the solution contains 1 mg of sodium.

Potassium chloride according to GOST 4234−77.

A standard solution of potassium*.
__________________
* Change No. 1 proposed in section 3, a standard solution of potassium, after the words «and handling», add the words: «Preserve the solutions in polyethylene or quartz dishes.» — Note the manufacturer’s database.

1,9067 g pre-dried in a drying Cabinet at a temperature of (100±5) °C for 1 h and cooled in a desiccator of potassium chloride is dissolved in water, transferred to a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.

1 cmof the solution contains 1 mg of potassium.

Standard solutions containing 1 mg/cmof sodium and potassium by the method of serial dilutions of each 10, 100 and 1000 times prepare standard solutions containing 100, 10 and 1 µg/cm, respectively, sodium or potassium.

Distilled water GOST 6709−72 distilled in a quartz apparatus and purified on ion-exchange column.

(Changed edition, Rev. N 2).

4. PREPARATION OF SAMPLES FOR ANALYSIS

4.1. Solutions comparison for determination of sodium and potassium are prepared in accordance with the table.1.

Table 1

The solutions comparison is prepared in a volumetric flasks with a capacity of 50 cm. To all flasks add 3 cmof nitric acid was adjusted to the mark with water, mixed and poured into a quartz or plastic utensils. If the measurement is performed in the flame acetylene-air, then all solutions of comparison for the measurement of potassium administered at 2.5 cmof solution of nitrate of sodium.

Solutions comparison, containing less than 1 µg/cmsodium or potassium, is prepared on the day of measurements.

To account for contamination introduced by the reagents in solutions for the construction of calibration curve prepare the control solution that contains nitric acid, water and sodium nitrate solution (in determining potassium in a flame acetylene-air).

(Changed edition, Rev. N 1, 2).

5. ANALYSIS

5.1. Sample sample weight (2,000±0,200) g was placed in a quartz, Teflon or glass glass from glass-carbon and clean contaminated surface by washing for 30 s 10 cmsolution NGO1:3 and 1:6 for samples in pieces and chips, respectively. The acid solution is drained, the sample is washed several times with water from probyvali holding a glass of sloping. Then in a Cup add 30 cmof nitric acid solution 1:3, cover with lid and decompose when heated. The solution was evaporated to wet salts, poured 20 cmof water, 6 cmof nitric acid, heated to dissolve the salts, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water, mixed, poured in Teflon, quartz glass or a glass of glassy carbon and close the lid. The decomposition of spend control experience.

If you use the flame acetylene-air, to determine the potassium take a charge or if the mass concentration of potassium, dilute the sample for introduction of a solution of sodium nitrate at the rate of 5 cmfor every 100 cmof solution.

Measure the atomic absorption or emission in the flame acetylene-air or butane-propane-air at the analytical line wavelength: 589,0 and 589,6 nm for sodium and 766,5 nm for potassium. When measuring apply the method of «limiting solutions», which means getting the samples to the sample solution and the two solutions comparisons, one of which gives a higher and the other lower count compared to the reference sample solution.

(Changed edition, Rev. N 2).

6. PROCESSING OF THE RESULTS

6.1. According to the obtained values of atomic absorption or emission for comparison of the solutions after subtracting the atomic absorption or emission control solution and corresponding weight fractions of sodium or potassium to build the calibration graph.

Mass fraction of sodium or potassium in percent is calculated by the formula

,

where is the mass concentration of the analyzed element in the sample solution taking into account the dilution factor, µg/cm;

 — mass concentration of the element in solution in the reference experiment, µ g/cm;

 — weight of sample, mg;

 — the volume of the sample solution, cm;

1000 — conversion factor from µg to mg.

(Changed edition, Rev. N 2)

.

6.2. The discrepancy between the highest and lowest of the three results of the parallel determinations should not exceed the values calculated according to the formula

,

while the largest discrepancy of the two results of the analysis of one sample obtained in one laboratory should not exceed the values calculated according to the formula

,

where and is the relative standard deviation of precision and reproducibility, respectively;

 — the arithmetic mean of the results of parallel measurements or analyses.

The values of relative average standard deviations are given in table.2.

Table 2

(Changed edition, Rev. N 1, 2)