GOST R 52520-2006

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  ГОСТ Р 52520-2006

GOST R 52520−2006 Platinum. Methods of atomic-emission analysis with arc excitation spectrum

GOST R 52520−2006

Group B59

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

Platinum

METHODS OF ATOMIC-EMISSION ANALYSIS
WITH AN ARC EXCITATION SPECTRUM

Platinum. Methods of arc 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 State Agency for the 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, JSC «Krasnoyarsk nonferrous metals plant them. V. N. Gulidova» (OJSC «Krastsvetmet»), JSC «Ekaterinburg plant for processing non-ferrous metals"

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 3-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 establishes spectrometry and spectrographic methods of atomic emission analysis (with an arc excitation spectrum) for determining the content of impurities, aluminum, bismuth, Germany, iron, gold, iridium, cadmium, calcium, cobalt, silicon, magnesium, manganese, copper, molybdenum, arsenic, Nickel, tin, osmium, palladium, rhenium, rhodium, ruthenium, lead, silver, antimony, tellurium, titanium, chromium and zinc / platinum.

Methods of analysis based on the evaporation and excitation of the atoms of the sample in arc discharge, measuring the intensity of emission of atoms determined of impurity elements and subsequent determination of these elements using the calibration dependences obtained by 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 6709−72 distilled Water. Specifications

GOST 14261−77 hydrochloric Acid of high purity. Specifications

GOST 18300−87 ethyl Alcohol rectified. 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 Spectrographic method of atomic-emission analysis with arc excitation

When the spectrographic method, using photographic registration of the emission spectra.

This method allows to determine the content of impurity elements in the intervals given in table 1.


Table 1 — Intervals of the contents of the designated elements

Percentage

4.1 Accuracy (trueness and precision)

4.1.1 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 uncertainty is with a probability of 0.95), the standard deviation of repeatability and reproducibility, 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

4.1.2 Correctness

To estimate the systematic error of this method for the determination of impurity elements in platinum are used as reference values certified values of mass fractions of elements in the state standard samples of composition of platinum GSO 7351−97 (set PL-35) 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.

4.1.3 Precision

4.1.3.1 Range of results four 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 4 according to GOST R ISO 5725−6 on average not more than once in 20 cases with proper use of the method.

4.1.3.2 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.

4.1.3.3 the results of the analysis of the same samples obtained by two laboratories in accordance with 4.3 to 4.7 of this standard, may vary with the excess indicated in the table 2 reproducibility limit according to GOST R ISO 5725−1 on average not more than once in 20 cases with proper use of the method.

4.2 Requirements

4.2.1 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 alloys.

4.2.2 qualifications of performers

To perform analysis allowed persons over the age of 18, trained in the prescribed manner and allowed to work independently on used equipment.

4.3 measurement Means, auxiliary devices, materials and reagents

Spectrograph with diffraction being a system of condensers, designed for producing, and photographing spectra in the range from 200 to 1000 nm with a reciprocal linear dispersion of 0.6−0.7 nm/mm.

Arc generator of AC or DC power up to 15 A.

Microphotometer designed to measure the optical density (blackening) of spectral lines.

Laboratory scales according to GOST 24104 with a limit of permissible absolute error of less than ±0.005 g.

Grinding machine graphite electrodes with a set of cutters.

Electrodes of graphite [1] 6 mm in diameter with a crater depth of 1−3 mm and a diameter of 4 mm.

Photographic plates of the spectral for normal blackening.

Contrast developer and fixer for photographic plates.

Electric stove with a closed spiral.

Drying Cabinet.

Glasses chemical resistant according to GOST 25336.

Hydrochloric acid OS.h. according to GOST 14261.

Rectified ethyl alcohol according to GOST 18300.

Distilled water according to GOST 6709.

Samples for calibration (samples of platinum with the previously established in the laboratory values of mass fraction of impurity elements).

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.

4.4 Sampling and sample preparation

4.4.1 Selection of laboratory samples from ingots or powder / platinum is carried out according to GOST R 52245.

4.4.2 Samples of platinum can enter the analysis in the form of ribbon, wire, shavings, sponge, powder.

4.4.3 Samples received for analysis in the form of tape, wire or shavings to remove the surface dirt is boiled in hydrochloric acid, diluted 1:1, for 10−15 min. the resulting solution was decanted, the sample was washed with distilled water by decantation 4−5 times and dried in air. Samples of the powder and sponge not treated with acid.

4.4.4 From samples of platinum received for analysis selected 4 sample, from the samples to the calibration or standard samples — 2 samples with a mass of (100±5) mg of each.

4.5 Preparation of equipment for measurement

4.5.1 Equipment ready to work according to the instructions. Operating modes of the instrument, the wavelengths of the analytical lines and lines of comparison that are recommended to perform the analysis presented in tables 3 and 4, respectively. For each designated item, choose one of the recommended wavelengths. The use of other lines and operating modes subject to receipt of the accuracy rate that rivals those in table 2.


Table 3 — Recommended operating modes

Table 4 — wavelengths of the analytical lines

In nanometers

4.5.2 electrode holders and devices are cleaned with alcohol from surface contamination.

4.5.3 Suspension of platinum is placed in a graphite crater electrode. Contradictator is a graphite rod sharpened to a hemisphere or truncated cone. When used as a driving source of a DC arc of the analyzed sample is the anode.

4.6 measurements

4.6.1 To obtain a calibration curve using standard samples of composition of platinum or samples for calibration. Spectra of each standard sample (sample for calibration) and a test sample is photographed under the same conditions. For each standard sample (for calibration) get two, and for the sample analyzed four spectrograms. For the mass concentration of magnesium, copper, and silver in the sample of more than 0.002% of the photography spectrum is carried out using a three-stage attenuator.

4.6.2 photographic Plates showing, rinsed in water, fixed, washed in running water and dried.

4.6.3 using microphotometry on each spectrogram to measure the blackening of analytical lines of the designated element and the surrounding background and calculate the difference of pochernenija . From the received values are transferred to the values using the table given in Appendix A. Using the values of and obtained for standard samples to build a calibration curve in the coordinates (, where is the mass fraction (%) of the analyzed element in the standard sample (sample of grabarov

CI).

4.6.4 For the calibration schedule, with four parallel values obtained for the four spectrograms for each sample, find the four results of parallel measurements of contents of each element impurities in the sample.

4.7 evaluation of the acceptability of the results of parallel measurements and obtaining the final result of the analysis

4.7.1 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 shown in table 2.

4.7.2 If the range of the results of four parallel samples () 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 four parallel measurements.

4.7.3 If the range of the results of four parallel measurements exceeds , spend four parallel determinations. Expect the critical range for up to eight parallel measurements according to the formula

, (1)

where is the standard deviation of repeatability.

If the received eight parallel measurements, the value () does not exceed the critical range , as a final result of the analysis taking the arithmetic mean of results of eight parallel measurements. Otherwise, as a final result of the analysis taking the median of the results of eight parallel measurements, if the regulations of the enterprise stipulate otherwise.

4.8 the Control precision of the analysis results

4.8.1 Control of 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.

4.8.2 verification of correct

The checking is carried out by analyzing standard samples of platinum. The samples used for control of correctness cannot 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).

5 Spectrometric method of atomic-emission analysis with arc excitation

When the spectrometric method, using a photoelectric method of recording emission spectra.

The method allows to determine the content of impurity elements in the intervals given in table 5.


Table 5 — Spacing of the content of determined elements

Percentage

5.1 Accuracy (trueness and precision)

5.1.1 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 uncertainty is with a probability of 0.95), the standard deviation of repeatability and reproducibility, the values of the critical range , intermediate precision and reproducibility limit depending on the mass fraction of the element — impurities are shown in tables 6−8.


Table 6 — indicators of the accuracy of the method. Determination of aluminium, bismuth, Germany, iron, gold, calcium, cobalt, silicon, magnesium, manganese, copper, molybdenum, arsenic, Nickel, tin, palladium, rhenium, rhodium, ruthenium, lead, silver, antimony, tellurium, titanium, chromium, zinc

Percentage

Table 7 — indicators of the accuracy of the method. Determination of iridium and osmium

Percentage

Table 8 — indicators of the accuracy of the method. Determination of cadmium

Percentage

5.1.2 Correctness

To estimate the systematic error of this method for the determination of impurity elements in platinum are used as reference values certified values of mass fractions of elements in the state standard samples of composition of platinum GSO 7003−93 (a set of Nozzles-21) and GSO 7351−97 (set PL-35) 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 defined elements — impurities in platinum at all levels of the designated contents.

5.1.3 Precision

5.1.3.1 the Range of results four definitions obtained for the same sample by one operator using the same equipment within the shortest possible time intervals may be greater than shown in tables 6−8 the critical range for 4 according to GOST R ISO 5725−6 on average not more than once in 20 cases with proper use of the method.

5.1.3.2 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 tables 6−8 limit intermediate precision according to GOST R ISO 5725−3 on average not more than once in 20 cases with proper use of the method.

5.1.3.3 results of the analysis of the same samples obtained by two laboratories may vary with the excess specified in tables 6−8 the reproducibility limit according to GOST R ISO 5725−1 on average not more than once in 20 cases with proper use of the method.

5.2 Requirements

5.2.1 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 alloys.

5.2.2 qualifications of performers

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

5.3 measurement Means, auxiliary devices, materials and reagents

Spectrometer with a generator of the arc is constant (AC) current or analytical complex on the base of the spectrograph medium dispersion analyzer emission spectra of Maes type and the generator of the arc is constant (AC) current.

Laboratory scales according to GOST 24104 with a limit of permissible absolute error of less than ±0.001 g.

Electrodes of graphite [1] 6 mm in diameter, sharpened to a truncated cone or hemisphere, and 4 mm in diameter with a crater depth of 1−3 mm.

Steel molds.

Grinding machine graphite electrodes with a set of cutters.

Electric stove with a closed spiral.

Glasses chemical resistant.

Hydrochloric acid OS.h. according to GOST 14261.

Rectified ethyl alcohol according to GOST 18300.

Distilled water according to GOST 6709.

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.

Samples for calibration (samples of platinum with the previously established in the laboratory values of mass fraction of impurity elements).

Allowed the use of other measurement means, auxiliary devices, materials and reagents, subject to obtaining accuracy, not inferior to those stated in tables 6−8.

5.4 Sampling and sample preparation

5.4.1 the Selection of laboratory samples from ingots or powder / platinum is carried out according to GOST R 52245.

5.4.2 Samples of platinum can enter the analysis in the form of ribbon, wire, shavings, sponge, powder.

5.4.3 Samples received for analysis in the form of tape, wire or shavings to remove the surface dirt is boiled in hydrochloric acid, diluted 1:1, for 10−15 min. the resulting solution was decanted, the sample was washed with distilled water by decantation 4−5 times and dried in air. Samples of the powder and sponge not treated with acid.

5.4.4 From laboratory samples of platinum have selected 4 sample, from the samples to the calibration or standard samples — 2 samples with a mass of (100±5) mg of each. Sample powder pressed into a graphite crater electrode.

5.5 Preparation of equipment for measurement

5.5.1 Equipment ready to work according to the instructions. The wavelengths of the analytical lines and operating modes of the spectrometer are shown in tables 9 and 10, respectively. For the determination of cadmium (at a mass fraction of less than 0.001%) and rhenium in arc DC carried out an additional survey under the conditions shown in table 10. The use of other analytical lines and operating modes subject to receipt of the accuracy rate, not inferior to those stated in tables 6−8.


Table 9 — Recommended wavelengths of the analytical lines

Table 10 — Recommended operating modes of the spectrometer

5.5.2 electrode holders clear alcohol from surface contamination.

5.6 measurements

5.6.1 a portion of the sample for calibration or test sample is placed in a graphite crater electrode. Contradictator is a graphite rod sharpened to a hemisphere or truncated cone. When used as a driving source of a DC arc linkage is the anode.

5.6.2 To obtain a calibration based on measurements taken of the intensity of the analytical lines of the determined elements and lines of comparison for the standard samples (calibration samples). For each of the identified elements choose one of the recommended analytical lines. The measurements were carried out according to the method of internal standard for the following elements: aluminum, iron, gold, iridium, silicon, copper, Nickel, tin, palladium, rhodium, ruthenium, antimony. As internal standard, choose a line of platinum 228,048 nm. For other elements, the analytical signal is the absolute value of the line intensity minus the background.

The measurements were carried out for two batches of standard samples of composition of platinum or samples for the calibration and get the average.

5.6.3 Receive a calibration based on relative or absolute intensity of the analytical lines of the determined elements from the mass fraction of these elements in standard sample (sample for graduation) to coordinate the program of the spectrometer.

5.6.4 Measured intensity of analytical lines of the determined elements for each of the four batches of samples.

5.6.5 using the calibration dependencies get four results of parallel measurements of the mass fraction of each analyzed element in the sample.

5.7 evaluation of the acceptability of the results of parallel measurements and obtaining the final result of the analysis

5.7.1 acceptance of the results of parallel measurements was evaluated in accordance with GOST R ISO 5725−6 by matching range, results () critical range given in tables 6−8.

5.7.2 If the range of the results of four parallel samples () 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 four parallel measurements.

5.7.3 If the range of the results of four parallel measurements exceeds , spend four parallel determinations. Expect the critical range for up to eight parallel measurements according to the formula

, (3)

where is the standard deviation of repeatability.

If the received eight parallel measurements, the value () does not exceed the critical range , as a final result of the analysis taking the arithmetic mean of results of eight parallel measurements. Otherwise, as a final result of the analysis taking the median of the results of eight parallel measurements, if the regulations of the enterprise stipulate otherwise.

5.8 the Control of accuracy of analysis results

5.8.1 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 , shown in tables 6−8.

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 tables 6−8.

5.8.2 verification of correct

The checking is carried out by analyzing standard samples of platinum. The samples used for control of correctness cannot 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

, (4)

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 tables 6−8).

Annex a (mandatory). Table of values of lg (l (l)/l (f)), corresponding to the measured values of Delta S/"gamma»

Appendix A
(required)

A table of values corresponding to measured values

The following table A. 1 serves for transmission of measured values and .

The table contains the results of the calculation according to the formula

, (A. 1)

where is the difference in the density of pochernenija on the plate;

 — contrast ratio.

We denote the total intensity of the line together with the background , the intensity of the background under the high line in the absence of the line . Since , the ratio of line intensity to the background intensity is determined by the formula

. (A. 2)

If the conditions of photographing the spectrum chosen so that the blackening of a line with a background and background in the absence of the line are in the normal range,

where . (A. 3)

Hence, using the expression derived .

Table A. 1 covers the most important practices for analytical work values from 0.05 to 1.9.

The table consists of two parts: the part covering values from 0.05 to 0.99, and part of the covering values from 1.00 to 1.9.

In the first part of the table in the first column are the values with two decimal places, the figures in the heads of others count from 0 to 9 indicate the third decimal place values .

For example, 0,537: in the first column find the value of 0.53 in the graph with figure 7 to determine the corresponding value of the logarithm 0,388.

The second part of the table built in a similar way with the difference that the first column lists the values with one decimal place and the numbers in the heads of other boxes represent the second after the decimal sign values .

For example, of 1.36: in the first column find the value of 1.3, in the graph from figure 6 find the value of logarithm of 1,341.

For values smaller than had 0.301, the value is negative the minus sign over the characteristic (±…).

Since , the table can be used to find the value corresponding to the values in any method of measurement.

If the contrast ratio is not measured, instead of the values in the table apply values , use this table in a similar way. If the measured value and 0.674 in the first column find the value of 0.67 in column 4 determine the meaning of the logarithm of 0,571.

It should be noted that the found thus the value of 0,571 represents not and . The precision of the analysis by the method of «three standards» the fact is almost no effect.


Table A. 1 — Values corresponding to measured values

Bibliography

[1] THE 3497−001−51046676−2001 Graphite electrodes for emission spectral analysis