GOST R 52521-2006

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  ГОСТ Р 52521-2006

GOST R 52521−2006 Platinum. Method of atomic-emission analysis with spark excitation spectrum

GOST R 52521−2006

Group B59

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

Platinum

METHOD OF ATOMIC-EMISSION ANALYSIS
WITH SPARK EXCITATION SPECTRUM

Platinum. Method of spark atomic-emission analysis

OKS 39.060

Date of introduction 2006−07−01

Preface

The objectives and principles of standardization in the Russian Federation established by the Federal law of 27 December 2002 N 184-FZ «On technical regulation», and rules for the application of national standards of the Russian Federation — GOST R 1.0−2004 «Standardization in the Russian Federation. The main provisions"

Data on standard

1 DEVELOPED by the Open joint-stock company «Prioksky nonferrous metals plant» (OJSC pztsm), a Public institution on formation of the State Fund of precious metals and precious stones of the Russian Federation, storage, holiday and use of precious metals and precious stones (Gokhran of Russia) under the Ministry of Finance of the Russian Federation

2 SUBMITTED by the Technical Committee for standardization TC 102 «Platinum metals"

3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology from February, 6th, 2006 N 4-St

4 INTRODUCED FOR THE FIRST TIME


Information about the changes to this standard is published in the annually issued reference index «National standards», and the text changes and amendments — in monthly indexes published information «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in a monthly information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet

1 Scope

This standard applies to affilirovannuju platinum bullion and powder with a mass fraction of platinum not less than 99.8%, designed for the production of alloys, semi-finished products, chemical compounds of platinum and other purposes.

The standard specifies atomic emission (spark excitation spectrum) method for determination of impurities, aluminum, bismuth, tungsten, germanium, gold, iron, iridium, cadmium, calcium, cobalt, silicon, magnesium, manganese, copper, molybdenum, arsenic, Nickel, tin, osmium, palladium, rhodium, ruthenium, lead, selenium, silver, antimony, tellurium, titanium, chromium, zinc and zirconium / platinum.

The method allows to determine the content of impurities in the intervals given in table 1.


Table 1 — Intervals of the contents of the designated elements

The method of analysis is based on the evaporation and excitation of the atoms of the sample in the spark discharge, the photoelectric registration of spectrum and measuring the intensity of the analytical lines of the determined elements and background. The relationship of the intensity of lines with the contents of the element in the sample is established by means of the calibration based on standard samples of composition of the platinum.

2 Normative references

This standard uses the regulatory references to the following standards:

GOST R 8.563−96 State system for ensuring the uniformity of measurements. Methods of measurement

GOST R ISO 5725−1-2002 Accuracy (trueness and precision) of methods and measurement results. Part 1. General provisions and definitions

GOST R ISO 5725−3-2002 Accuracy (trueness and precision) of methods and measurement results. Part 3. Intermediate indicators the precision of a standard measurement method

GOST R ISO 5725−4-2002 Accuracy (trueness and precision) of methods and measurement results. Part 4. The main methods of determining the correctness of a standard measurement method

GOST R ISO 5725−6-2002 Accuracy (correctness and precision) of methods and measurement results. Part 6. The use of precision values in practice

GOST R 52245−2004 Platinum affilirovannaja. Specifications

GOST 10157−79 Argon gaseous and liquid. Specifications

GOST 14261−77 hydrochloric Acid of high purity. Specifications

GOST 18300−87 ethyl rectified technical. Specifications

GOST 24104−2001 laboratory Scales. General technical requirements

GOST 25336−82 Glassware and equipment laboratory glass. The types, basic parameters and dimensions

Note — When using this standard appropriate to test the effect of reference standards in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet or published annually by the information sign «National standards» published as on January 1 of the current year and related information published monthly indexes published in the current year. If the reference document is replaced (modified), then the use of this standard should be guided by the replaced (modified) document. If the reference document is cancelled without replacement, then the situation in which the given link applies to the extent that does not affect this link.

3 Terms and definitions

This standard applies the terminology according to GOST R ISO 5725−1 and GOST R 8.563.

4 Accuracy (trueness and precision) of the method

4.1 indicators of the accuracy of the method

Indicators of accuracy of the method: the limit of absolute error of the results of the analysis (the boundaries of the interval in which the measurement error is determined with a probability of 0.95), the standard deviation of repeatability and intermediate precision, the values of the critical range , intermediate precision and reproducibility limit depending on the mass fraction of the element — impurities are shown in table 2.


Table 2 — indicators of the accuracy of the method (0,95)

Percentage

4.2 Correctness

To estimate the systematic error of the present method for the determination of all elements (impurities) in platinum should be used as a reference certified value mass fraction of elements in the state standard samples of composition of platinum (set PL-35) GSO 7351−97 or other GEO, the next set of detectable elements and metrological characteristics.

Systematic error of the method at the significance level 5% nonsignificant according to GOST R ISO 5725−4 for all determined elements (impurities) in platinum at all levels of the designated contents.

4.3 Precision

4.3.1 the Range of results of the five definitions obtained for the same sample by one operator using the same equipment within the shortest possible time intervals that may exceed the specified in table 2, the critical range for 5 according to GOST R ISO 5725−6 on average not more than once in 20 cases with proper use of the method.

4.3.2 within a single laboratory result analysis of the same sample obtained by different operators using the same equipment on different days, can vary with the excess specified in table 2 of the limit of intermediate precision according to GOST R ISO 5725−3 on average not more than once in 20 cases with proper use of the method.

4.3.3 Results of analysis of samples of the same material, obtained in two laboratories in accordance with sections 6, 7, 8, 9 of this standard may vary in excess of the limit of reproducibility according to GOST R ISO 5725−1 specified in table 2, on average not more than once in 20 cases with proper use of the method.

5 Requirements

5.1 General requirements and safety requirements

General requirements, requirements for security of works and environmental safety — according to the normative documents on the General requirements for methods of analysis of precious metals and their alloys.

5.2 qualifications of performers

The analysis allowed persons over the age of 18, trained in the prescribed manner and allowed to work independently on the emission spectrometer.

6 measurement Means, auxiliary devices, materials and reagents

Optical emission spectrometer with spark excitation source spectrum and the working wavelength range 120−700 nm.

Laboratory scales according to GOST 24104 with a limit of permissible absolute error of less than ±0.01 g.

Milling machine.

The press and the mold.

Argon gas according to GOST 10157.

Flap fabric such as calico.

Rectified ethyl alcohol according to GOST 18300.

Distilled water.

Hydrochloric acid of high purity according to GOST 14261.

Glasses glass with a capacity of 100 cmaccording to GOST 25336.

Standard samples of composition of platinum with an error of certified values of the content of impurities not exceeding 1/3 of the value of the absolute error of the present method for each level in grades.

Allowed the use of other measurement means, auxiliary devices, materials and reagents, subject to obtaining accuracy rate that rivals those in table 2.

7 Sampling

7.1 the Selection of laboratory samples for analysis from the ingots or powder / platinum is carried out in accordance with GOST R 52245.

7.2 Samples received for analysis in the form of ingots, rods, plates, strips, shavings and powder.

7.3 requirements for the size and mass of the samples are determined depending on the used spectrometer.

7.4 the surface of the rods and plates should be flat, and processed by cutting or grinding, the tape surface should be smooth and without delamination.

8 Preparation for measurement

8.1 Samples in the form of ingots, rods, plates, wipe with a cloth moistened with rubbing alcohol.

8.2 Samples in the form of ribbons, shavings boiled in hydrochloric acid for 3−5 min to remove surface contamination. The resulting solution was decanted, the sample was washed 6−7 times with distilled water by decantation and dried in air. From the sample in the form of chips or powder taken weighed 30 g and the press force 500 kN per tablet.

8.3 the Spectrometer is ready to work according to the instruction manual of the device. Carry out purging the system with argon for 3 seconds.

The recommended operating modes of the spectrometer:

The wavelengths of the analytical lines is recommended to perform the analysis shown in table 3. Background it is recommended to measure the wavelength 310,50 or 200,86 nm.


Table 3 — wavelengths of the analytical lines

9 measurements

9.1 To obtain the calibration dependencies consistently reinforce the cell spark discharge standard samples of composition of platinum and carry out measurement of intensity of analytical lines of the determined elements and background. For graduation choose two or more standard samples of composition of platinum so that the content of each analyzed element — impurities in the sample was within the interval between the highest and lowest values of the content of this element in the standard samples. For each standard sample and take measurements at five different points on the surface. Before measuring at each point conduct uzyskiwania surface for 20 s.

9.2 Calibration relationships are obtained in the coordinates: the average value of the intensity of the analytical lines of the determined elements (with background subtracted) for five points on the surface of the specimen — mass fraction of the element in the standard sample.

9.3 Measure the intensity of the analytical lines of the determined elements and background to the five points of the surface of the sample at 7.1.

9.4 using the calibration dependencies, find five parallel values of the mass fraction of each analyzed element in the sample.

10 assessment of the admissibility of the results of parallel measurements and obtaining the final result of the analysis

The acceptability of the results of parallel measurements was evaluated in accordance with GOST R ISO 5725−6 by matching range, results () with the critical range . The critical range is calculated by the formula

, (1)

where  — the ratio of the critical range, where

is the number of parallel definitions;

 — standard deviation of repeatability.

The values of and are shown in tables 2 and 4, respectively.


Table 4 — the coefficients of the critical range

If the range of the results of five parallel measurements () does not exceed the critical range , all the results and recognise acceptable for the final result of the analysis take the average of results of five parallel measurements.

If the range of the results of five parallel measurements exceeds , carried out for five parallel measurements.

If received ten parallel measurements value () does not exceed the critical range , as a final result of the analysis take the average of results of ten parallel measurements. Otherwise, as a final result of the analysis taking the median of the results of ten parallel measurements.

11 Control of accuracy of analysis results

11.1 Control intermediate precision and reproducibility

When monitoring intermediate precision (variable factors of the operator and time) is the absolute difference of the two results of the analysis of the same sample obtained by different operators using the same equipment on different days, should not exceed the limit of intermediate precision specified in table 2.

Under the control of the reproducibility of the absolute disparity of the two results of the analysis of the same samples, obtained in two laboratories, in accordance with the requirements of this standard must not exceed the limit of reproducibility shown in table 2.

11.2 verification of correct

The checking is carried out by analyzing standard samples of composition of platinum. The samples used for control of correctness should not be used to obtain the calibration dependencies.

When checking the difference between the analysis result and the accepted reference (certified) value of the content of element impurities in the standard sample should not exceed a critical value .

The critical value is calculated by the formula

, (2)

where  — the error of setting the reference (certified) value of the content of element impurities in the standard sample;

 — the limit of absolute error of the result of the analysis (values shown in table 2).