GOST 26880.1-86

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  ГОСТ 26880.1-86

GOST 26880.1−86 (ST SEV 5010−85 — ST CMEA 5013−85, ST SEV 5509−86, ST SEV 5511−86) Lead. Atomic absorption method of analysis (with Amendments No. 1, 2)

GOST 26880.1−86
(ST CMEA 5010−85-
ST SEV 5013−85,
ST SEV 5509−86,
ST SEV 5511−86)*
_______________________
* The designation of the standard.
Changed the wording, Rev. N 1.

Group B59

STATE STANDARD OF THE USSR

LEAD

Atomic absorption method of analysis

Lead. Atomic-absorption method of analysis

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 on standards of 25 April 1986 No. 1072

REPLACE GOST 20580.10−78, GOST 20580.11−78

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 8, 1987, ICS # 10, 1991


This standard establishes the atomic absorption method for the determination of metal components that lead brands, S1S, S1, S2S, S2, S3S and S3 for the mass concentration, %:

Atomic absorption method for the determination of impurities in the lead without enrichment based on dissolving the samples in nitric acid and the measurement of atomic absorption at the analytical lines of the determined elements with the introduction of analyte solutions and comparison in the flame of acetylene-air and nitrous oxide-acetylene.

Method for enriching the sample based on the decomposition of samples with nitric acid, deposition of the main mass of lead in the form of nitrate, the evaporation of the resulting solution to a small volume and dimension in this atomic absorption analytical lines of the determined elements in the introduction of this and comparison of solutions in the flame of acetylene-air and nitrous oxide-acetylene.

The standard fully complies ST SEV 5010−85 — ST CMEA 5013−85, ST SEV 5509−86 and ST SEV 5511−86.

(Changed edition, Rev. N 1, 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 25086−87.

1.2. Control of the correctness is carried out according to GOST 25086−87 by a method of additives or by standard samples of lead C3-S0 N (1591−1602)-79 State register of measures and measuring instruments of the USSR.

Sample standard sample depending on the contents of the monitored item selected in the form of sawdust or shavings and conduct analysis in accordance with sec. 5 (sawdust get a file, chip — using a drill).

The checking is carried out at least once a month, and when changing reagents, solutions, instruments, after a long break.

1.1, 1.2. (Changed edition, Rev. N 2).

1.3. The numerical value of the result of the analysis must end with the number of discharges, and the corresponding value of permissible differences of parallel measurements.

2. SAFETY REQUIREMENTS

2.1. Safety requirements — according to GOST 8857−77 with additions.

2.1.1. In the analysis of lead used reagents and materials which have a deleterious effect on the human body: lead, nitric, hydrofluoric and tartaric acid, the ferrous nitrate of mercury, acetylene, nitrous oxide, maximum permissible concentrations in the working area of industrial premises are as follows (in mg/m): for lead and its inorganic compounds is 0.01, the time-weighted average 0,007 (hazard class 1); nitric acid and its vapors 2 (hazard class 3); vapor fluoride-hydrogen acid of 0.5 (hazard class 2); mercury nitrate, ferrous 0,2, time-weighted average MPC of 0.05 (hazard class 1); acetylene 0.5 (hazard class 2), nitrogen oxides (calculated as NO) 5 (hazard class 3).

These chemicals and materials have on the human body the following adverse effects:

lead can enter the body through respiratory organs, gastrointestinal tract, skin, and cause damage to the nervous, blood and cardiovascular system, upper respiratory tract, gastrointestinal tract, liver, kidneys, eyes and skin, and may also cause metabolic and endocrine disorders;

concentrated nitric acid when in contact with skin causes severe burns, dilute solutions may cause eczema. Dangerous smoke containing nitrogen dioxide (NO), nitrogen pentoxide (NO) and mist of nitric acid, which, when excessive concentrations irritating to the respiratory system and can cause tooth decay, conjunctivitis, and lesions of the cornea;

a pair of hydrofluoric acid at excessive concentrations strongly irritate the upper respiratory tract and mucous membranes (the threshold irritant — 0,008 mg/DM), can cause acute and chronic poisoning, changes in the digestive organs and the respiratory, cardiovascular system, as well as changes in the composition of the blood. Hydrofluoric acid prijigauschee effect on the skin, causing dermatitis and ulcers;

tartaric acid irritating to mucous membranes and the skin;

ferrous nitrate mercury is poisonous if swallowed, by skin contact and inhalation of dust. The poisoning with mercury salts is manifested headache pain, redness, swelling and bleeding of the gums, stomatitis, swelling of lymphatic and salivary glands, colitis. In severe poisoning develop drastic changes in the kidneys, the mucous membrane of the stomach and duodenum, liver;

acetylene and nitrous oxide cause suffocation due to displacement of oxygen from the lungs.

When working with lead, nitric, hydrofluoric and tartaric acids, the ferrous nitrate of mercury should be guided by the safety requirements according to GOST 3778−77*, 11125−84 GOST, GOST 5817−77, 4521−78 GOST, GOST 10484−78.
________________
* On the territory of the Russian Federation GOST 3778−98. Here and further. — Note the manufacturer’s database.

In the use and operation of compressed, liquefied and dissolved gases in the process of analysis should follow the rules of arrangement and safe operation vessels working under pressure, approved by Gosgortekhnadzor of the USSR.

(Changed edition, Rev. N 2).

2.1.2. To prevent entering the working area of harmful substances released during the spraying of the analyzed solutions in the flame and bad acting on the body working in quantities exceeding the maximum allowable concentration, the burner of the atomic absorption spectrophotometer should be located inside the exhaust device.

2.1.3. Preparation of samples for analysis must be carried out in cabinets equipped with local exhaust ventilation.

2.1.3. The content of harmful substances in the air of working zone generated during the analysis should not exceed the maximum allowable concentrations according to GOST 12.1.005−88; to control methodical instructions approved by the USSR Ministry of health, or by the techniques corresponding to the requirements of GOST 12.1.016−79.

(Added, Rev. N 2).

2.1.4. Electrical safety when working with electrical installations — according to GOST 12.1.019−79.

3. APPARATUS, MATERIALS, REAGENTS and SOLUTIONS

Atomic absorption spectrophotometer with all accessories and radiation sources for silver, copper, zinc, bismuth, arsenic, tin, antimony, iron, magnesium and calcium. In the determination of iron requires the use of the nebulizer and the burner, made of a material not containing iron.

Scales analytical and torsion.

Nitric acid high purity of the brand OS.H. 18−4 OS.H. 21−5 GOST 11125−84 and solutions 1:2, 1:3 and 1:6.

Hydrofluoric acid according to GOST 10484−78.

Tartaric acid according to GOST 5817−77.

Lead or lead nitrate high purity with a mass fraction, %, not more:

The solution of lead:

of metallic lead in the glass with a capacity of 600 cmdissolve 25.0 g of lead 150 cmof nitric acid (1:3), evaporated to wet salts, add 5 cmof nitric acid and 150 CCof water. Heated to dissolve the salts and transferred to a volumetric flask with a capacity of 250 cm, cooled, adjusted to the mark with water and mix;

of nitrate of lead in a beaker with a capacity of 400 cmdissolve 40.0 g of lead nitrate in 150 cmof water, add 5 cmof nitric acid, transferred to a volumetric flask with a capacity of 250 cm, was adjusted to the mark with water and mix.

1 cmof the solution contains 0.1 g of lead.

Mercury ferrous nitrate according to GOST 4521−78 or oxide according to GOST 4520−78.

The granular silver or silver nitrate according to GOST 1277−75.

Standard silver solution:

metal silver: 0,1000 g of silver dissolved in 10 cmof nitric acid (1:3) under heating. The solution was cooled, added to 50 mg of the ferrous nitrate of mercury, 5 cmof nitric acid, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix;

of nitrate of silver: 0,1575 g of silver nitrate dissolved in 15 cmof water, add 50 mg of the ferrous nitrate of mercury, 5 cmof nitric acid, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

The solution was stored in a dark place.

1 cmof the solution contains 1 mg of silver.

Copper GOST 859−78*.
______________
* On the territory of the Russian Federation GOST 859−2001. — Note the manufacturer’s database.

A standard solution of copper.

1,000 g of copper, washed with a solution of nitric acid (1:6), is dissolved in 30 cmof nitric acid by heating, the solution was cooled, 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 copper.

Zinc GOST 3640−79*.
______________
* On the territory of the Russian Federation GOST 3640−94. — Note the manufacturer’s database.

Standard solution of zinc.

1,000 g of zinc is dissolved in 25 cmof a solution of nitric acid (1:3), transferred into 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 zinc.

Bismuth GOST 10928−75*.
______________
* On the territory of the Russian Federation GOST 10928−90. — Note the manufacturer’s database.

A standard solution of bismuth.

1,000 g of bismuth dissolved in 20 cmof nitric acid (1:3) by heating, the solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm, add 10 cmof nitric acid was adjusted to the mark with water and mix.

1 cmof the solution contains 1 mg of bismuth.

Arsenic metal.

Standard solution of arsenic.

1,000 g of arsenic dissolved in 10 cmof nitric acid by heating under a lid. The solution was cooled, 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 arsenic.

Tin GOST 860−75.

A standard solution of tin.

1,000 g of tin are dissolved in 50 cmmixture of nitric, hydrofluoric acid and water (15:10:25) in PTFE beaker by heating, the solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water, mixed and poured into plastic containers.

1 cmof the solution contains 1 mg of tin.

Antimony GOST 1089−82.

Standard solution of antimony.

1,000 g of antimony is dissolved in 15 cmof nitric acid with addition of 15 g of tartaric acid by heating, the solution was cooled, 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 antimony.

Iron metal, reduced hydrogen or carbonyl.

Standard solution of iron.

1,000 grams of iron are dissolved in 15 cmof nitric acid by heating, the solution was cooled, added to 10 cmof nitric acid, transferred into 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 iron.

Magnesium metal according to GOST 804−72* or magnesium oxide according to GOST 4526−75.
______________
* On the territory of the Russian Federation GOST 804−93. — Note the manufacturer’s database.

Standard solution of magnesium.

1,000 g of magnesium or 1,6583 g pre-calcined in a muffle furnace at (700±25) °C for 1 h and cooled in desiccator, the magnesium oxide is dissolved in 10 cmof nitric acid by heating, the solution was cooled, 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 magnesium.

Calcium carbonate according to GOST 4530−76.

A standard solution of calcium.

2,497 g pre-dried in an oven at (100±5) °C for 1 h and cooled in a desiccator of calcium carbonate dissolved in 15 cmof nitric acid by heating, the solution was cooled, 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 calcium.

Of the solutions of the identified elements by the method of serial dilutions of each 10, 100 and 1000 times prepare standard solutions containing each element by 100, 10 and 1 µg/cm, respectively (solution with a content of the designated element 1 µm/cmprepared only for silver).

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

Potassium chloride according to GOST 4234−77 with a mass fraction of calcium and magnesium not more than 0.001 and 0.0005%, respectively, a solution of 40 g/DM.

Cesium chloride high purity with a mass fraction of calcium and magnesium not more than 0.001 and 0.0005%, respectively, a solution of 10 g/DM.

(Changed edition, Rev. N 1, 2).

4. PREPARATION FOR ASSAY

4.1. Method for the determination of silver, copper, zinc, bismuth, arsenic, tin, antimony, iron, magnesium and calcium without enrichment

Solutions comparison for determining the above elements is prepared in accordance with the table.1. To account for contamination introduced by the reagents in the solutions to build calibration curve for each element prepared control solution. This solution bring all reagents introduced into the solutions of comparison, in addition to the standard solution. The volume control and each solution comparisons is equal to 100 cm. To all flasks add 5 cmof nitric acid and 1 g of tartaric acid. In solutions comparison of silver, bismuth, arsenic, tin, zinc, copper, iron, antimony was added to a solution of lead in an amount corresponding to the content of lead in sample solution according to the linkage. Solutions was adjusted to the mark with water and mix.

In solutions comparison for the determination of calcium and magnesium in each flask add 10 cmof a solution of potassium chloride or cesium chloride, if the measurement is performed in the flame nitrous oxide-acetylene. In solutions comparison of silver is added to 50 mg of ferrous nitrate or oxide of mercury.

Table 1

Preparation of solutions comparison method (without enrichment)

To measure the absorption of copper, zinc, iron in diluted solutions prepared a second series of solutions comparison that does not add lead. The recommended mass fraction in solutions comparison for copper is from 1.0 to 5.0 mg/cm; for iron and zinc from 2.0 to 10.0 µg/cm.

Solutions comparison, containing less than 1 µg/cmof the identified elements, prepared on the day of measurements.

(Changed edition, Rev. N 1, 2).

4.2. Method for the determination of silver, copper, zinc, bismuth, iron, arsenic, tin and antimony enrichment

Solutions comparison for determining the above elements is prepared in accordance with the table.2. The volume of each solution comparisons is equal to 100 cm. To all flasks add 5 cmof nitric acid was adjusted to the mark with water and mix. The control solution is prepared in accordance with clause 4.1.

In comparison, the solutions of silver are added to 50 mg of ferrous nitrate or oxide of mercury.

Table 2

Preparation of solutions comparison method (with enrichment)

(Changed edition, Rev. N 1, 2).

5. ANALYSIS

5.1. Decomposition of the samples and the concentration of impurities

5.1.1. The decomposition of samples during the determination of silver, copper, zinc, bismuth, arsenic, tin, antimony, iron, magnesium and calcium without enrichment

A portion of sample weighing (1,000±0,200) to (4,000±0,500) g for copper, silver, bismuth, tin, iron, and calcium (1,000±0,200) to (2,000±0,200) g for zinc, magnesium, antimony and arsenic, depending on the concentrations of the determined elements were placed in a glass with a capacity of 250 cmand clean the contaminated surface by washing for 30 with 10 cmof nitric acid (1:3) 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. The sample is then placed in Teflon or quartz dishes, or utensils from glassy carbon, add 1 g of tartaric acid, 20−40 cmof nitric acid (1:3), cover with lid and decompose when heated. The solution was evaporated to wet salts, poured 20 cmof water 5 cmof nitric acid, heated to dissolve the salts, add 50 mg of ferrous nitrate or oxide of mercury and 10 cmof a solution of potassium chloride or cesium chloride, if the measurement of calcium or magnesium is carried out in a flame nitrous oxide-acetylene, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix. If the sample is not determined by the calcium or magnesium, it is possible to decompose it in a glass beaker, where they spent cleaning the sample.

When the content of zinc and iron from 0.1 to 0.2% and copper from 0.05 to 0.2% sample solution was diluted in 5 time for what 10 cmof the solution transferred to a volumetric flask with a capacity of 50 cm, add 2 cmof nitric acid was adjusted to the mark with water and mix.

In the case of iron determination the sample must be umanista.

5.1.2. The decomposition of the sample and the concentration of antimony, tin and arsenic

A sample of lead cut into pieces weighing 50−500 mg and take charge weight (40,000±1,000) g where the mass fraction of the designated impurities from 3·10to 2·10% (20,000±1,000) g where the mass fraction of antimony, arsenic and tin, more than 2·10%. The sample was placed in Teflon beaker or a glass of glassy carbon with a capacity of 400−500 cm(Cup pre-made label 200 cm) and clean the contaminated surface by washing for 30 s 30 cmof nitric acid (1:3) and (1:6) for samples cut in pieces and chips, respectively. The acid solution is decanted and the sample washed several times with water from probyvali holding a glass of sloping. Then in a glass pour 1.5−2.0 cmhydrofluoric acid and 100−150 cmof nitric acid (1:3) depending on the sample samples. The sample is dissolved by heating. The solution is heated to boiling, add 100−150 cm(depending on sample) boiling (~80 °C) nitric acid. Acid is gradually added with vigorous stirring a solution of fluoropolymer a stick. In a precipitate of nitrate of lead. The solution above the sediment was boiled down to 200 cmand cooled in running water for 1 h. the Solution was decanted into another glass (labeled 100 cm). The precipitate is washed twice with nitric acid in portions of about 15 cm, carefully mixing. After settling, the wash solution was decanted into a glass with a basic solution. The precipitate is discarded. The solution was evaporated to a volume of 100 cm, while again there is a residue of lead nitrate. Solution and the precipitate was cooled for 20 min and decanted into a Teflon beaker with a capacity of 250 cm. The precipitate is washed with 5 cmof nitric acid. Wash solution poured into the same Teflon beaker. The solution is evaporated to dryness, poured 5cmof water, 1.5 cmof nitric acid, the sample is heated to dissolve the salts, add 10−25 mg ferrous nitrate or oxide of mercury, is transferred to a measuring cylinder with a capacity of 25 cm, is adjusted with water to 15 cm. The solution was stirred, pouring it several times from the graduated cylinder into the glass, which carried out the evaporation, and Vice versa. The solution is stored in Teflon beaker, covering it with a lid. The decomposition of spend control experience for an amendment in the result analysis.

When the mass fraction of antimony and arsenic from 4·10to 1·10% sample solution diluted 5 times, why 5 cmthe solution is transferred to a volumetric flask with a capacity of 25 cm, add 1 cmof nitric acid was adjusted to the mark with water and mix.

The atomic absorption of tin is measured from the undiluted solution.

This same method without the addition of hydrofluoric acid to enrich the sample with the purpose of determination of low concentrations of silver, copper, zinc, bismuth, and iron, using a portion of the sample weighing 10 g. Reduction sample sample to 10 g reduces the time of concentration by

Mesa.

5.1.3. Decomposition of samples and concentration of silver, copper, zinc, bismuth, and iron

Weighed samples of lead weight (10,000±1,000) g cut into pieces weighing 50−500 mg, the sample presented a large piece, placed in a heat-resistant glass with a capacity of 400−500 cm(Cup pre-made label to 100 cm) and clean the contaminated surface by washing for 30 s in 20 cmof nitric acid (1:3) and (1:6) for samples cut in pieces and chips, respectively. The acid solution is decanted and the sample washed several times with water from probyvali holding a glass of sloping. The sample is then dissolved in 60 cmof nitric acid (1:2) when heated. The solution is heated to boiling, add 60 cmof boiling (~80 °C) nitric acid. Acid is added gradually with vigorous stirring of the solution with a glass rod. In a precipitate of nitrate of lead.

The solution is evaporated to a volume of 100 cmand cooled in running water for 1 h, then it is decanted into a quartz Cup or glass Teflon (PTFE in glass evaporation goes on more quietly, without splashing). The precipitate is washed twice with nitric acid in portions of 10 cm, mixing thoroughly, and drop. Wash solution after settling was decanted into a quartz Cup or Teflon beaker with a basic solution and evaporated to dryness. Then pour 10 cmof water, 2 cmof nitric acid, heated to dissolve the salts, add 10−15 mg of ferrous nitrate or oxide of mercury and transferred to a volumetric flask with a capacity of 25 cm. The decomposition of spend control experience for an amendment in the result analysis.

When concentration of impurities from 2·10% and above the sample is transferred to a volume of 100 cm, increasing the amount of nitric acid to 5 cm.

In the case of iron determination sample should be otmag

nicheno.

5.1.1−5.1.3. (Changed edition, Rev. N 1, 2).

5.2. Measurement of atomic absorption

Measure the atomic absorption of copper, silver, bismuth, iron, zinc, antimony in the flame acetylene-air, atomic absorption of arsenic in the flame nitrous oxide-acetylene atomic absorption of tin, calcium, and magnesium can be measured in both flames. Use analytical lines (wavelengths in nm):

The measurement is performed in the mode «absorption» method «limiting solutions» with a record on the recording potentiometer. The method of «limiting solutions» is to obtain the counts for 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. Solutions and comparison samples photometric twice.

(Changed edition, Rev. N 1, 2).

6. PROCESSING OF THE RESULTS

6.1. According to the obtained values of atomic absorption solutions comparison, after subtracting the value of the atomic absorbance of control solution and corresponding mass concentrations of the identified elements to build a calibration curve.

The result in µg/cmcount to obtain the result in percent 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.

The final result of the analysis be the arithmetic mean of results of three parallel measurements.

(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 squared deviations of convergence and reproducibility are given in table.3.

Table 3

The values of relative average squared deviations