GOST R ISO 13898-1-2006

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  ГОСТ Р ИСО 13898-1-2006

GOST R ISO 13898−1-2006 Steel and cast iron. Spectrometer of atomic emission with inductively coupled plasma method for the determination of Nickel, copper and cobalt. Part 1. General requirements

GOST R ISO 13898−1-2006

Group B39

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

Steel and cast iron

SPECTROMETER OF ATOMIC EMISSION WITH INDUCTIVELY
BOUND BY THE PLASMA METHOD FOR THE DETERMINATION OF NICKEL, COPPER AND COBALT

Part 1

General requirements

Steel and iron. Inductively coupled plasma atomic emission spectrometric method
for determination of nickel, copper and cobalt contents. Part 1. General requirements

OKS 77.080.01
AXTU 0709

Date of introduction 2008−01−01

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 PREPARED AND SUBMITTED by the Technical Committee for standardization TC 145 «monitoring Methods of steel products"

2 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology of December 21, 2006 No. 326-St

3 this standard is identical with ISO 13898−1:1997 «Steel and cast iron. Determination of Nickel, copper and cobalt. Spectrometric method of atomic emission with inductively coupled plasma. Part 1. General requirements and sampling» (ISO 13898−1:1997 «Steel and iron — Determination of nickel, copper and cobalt contents — Inductively coupled plasma atomic emission spectrometric method. Part 1: General requirements and sample dissolution»).

The name of this standard changed with respect to names specified international standard for compliance with GOST R 1.5−2004 (subsection 3.5).

In applying this standard it is recommended to use instead of the referenced international standards corresponding national standards of the Russian Federation, details of which are given in the Appendix With

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 specifies the spectrometer of atomic emission with inductively coupled plasma method for determination of Nickel, copper and cobalt in unalloyed steels and cast irons in the range are given in table 1.


Table 1

This standard specifies General requirements for the analysis, preparation and dissolution of the analyzed samples and the methods of calculation and the procedures for assessing the accuracy of individual methods according to ISO 13898−2, ISO 13898−3, ISO 13898−4.

The standard covers two methods of determining the mass fraction of elements in the analyzed solutions with and without using internal standard.

2 Normative references

This standard uses the regulatory references to the following international standards:

ISO 385−1:1984 laboratory Glassware glass. Burette. Part 1. General requirements

ISO 648:1977 laboratory Glassware glass. Pipette with one mark

ISO 13898−2:1997 Steel and iron. Determination of Nickel, copper and cobalt. Spectrometric method of atomic emission with inductively coupled plasma. Part 2. Determination of Nickel content

ISO 13898−3:1997 Steel and iron. Determination of Nickel, copper and cobalt. Spectrometric method of atomic emission with inductively coupled plasma. Part 3. Determination of copper content

ISO 13898−4:1997 Steel and iron. Determination of Nickel, copper and cobalt. Spectrometric method of atomic emission with inductively coupled plasma. Part 4. Determination of cobalt

ISO 14284:1996 Steel and iron. Selection and preparation of samples for chemical analysis

3 the essence of the method

The sample is dissolved in a mixture of hydrochloric and nitric acid, diluting to the specified volume. With addition of scandium, or yttrium as internal standard. Spray the solution into plasma atomic emission spectrometer to measure the intensity of light emission of each object or simultaneously with the measurement of radiation from scandium or yttrium. Examples of analytical lines given in table 2.


Table 2

4 Reagents and solutions

Unless otherwise specified, use reagents of the established analytical purity, distilled water, further purified by distillation or otherwise.

4.1 Pure iron, containing less than 0,0001% of each designated item.

4.2 Hydrochloric acid of high purity with a density of 1.19 g/cm, diluted 1:1.

4.3 Nitric acid high purity with a density of 1.40 g/cm, diluted 1:1.

4.4 Solution of scandium as internal standard corresponding to 1 g/DM.

Weighed with an accuracy of 1 mg 1,534 g of scandium oxide with purity of more than 99.98% of transferred in chemical beaker with a capacity of 500 cmand dissolved in 40 cm of nitric acid (4.3). The solution is quantitatively transferred into a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.

1 cm of the internal standard solution contains 1 mg of scandium.

4.5 Solution of yttrium as internal standard corresponding to 1 g/DM.

Weighed with an accuracy of 1 mg of 1,270 g of an oxide of yttrium of a purity of more than 99.98% of transferred in chemical beaker with a capacity of 500 cmand dissolved in 50 cmof hydrochloric acid (4.2). The solution is quantitatively transferred into a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.

1 cmof the internal standard solution contains 1 mg of yttrium.

4.6 Standard solutions of the determined elements.

Prepare the standard solutions for each element according to ISO 13898−2, ISO 13898−3, ISO 13898−4.

5 Instrument

All volumetric glassware should be class A, the corresponding ISO 385−1 ISO 648 depending on the type of dishes.

Analytical scale not lower than 2nd accuracy class with the greatest redistribution weighing 250 g.

5.1 Atomic emission spectrometer with inductively coupled plasma as excitation source

After setting up the spectrometer according to 7.4.1 must meet the requirements specified in 5.1.1 to 5.1.3.

The spectrometer can be simultaneous or sequential. If the spectrometer sequential measurement equipped with an additional device for simultaneous measurement line internal standard (scandium or yttrium), it can be used in the method using internal standard. If the spectrometer serial operation does not have this device, the internal standard cannot be used and you should apply another method without internal standard.

5.1.1 Short-term stability

Definition of short-term stability is given in A. 1.3 (Annex A).

Expect the standard deviation of ten measurements of absolute or relative intensity of the emission of the most concentrated calibration solution for each element.

The relative standard deviation should not exceed 0.4% of the average value of the absolute or relative intensity.

5.1.2 determination of the detection limit and the concentration equivalent to the background radiation, given in A. 1.1 and A. 1.2 (Annex A).

The concentration equivalent to the background radiation, and the detection limit calculated for analytical lines in a solution containing only one analyte element.

The obtained values should be less than the values given in table 3.


Table 3

5.1.3 linearity of calibration curve

The calculation of calibration curves is given in A. 2. The linearity of the calibration curve checked by calculating the correlation coefficient. The obtained value of this ratio should be more than 0,999.

6 Sampling

Sampling — ISO 14284.

7 Preparation and analysis

7.1 Linkage of the sample

A portion of the sample with a mass of 1,000 g weighed with an accuracy of 1 mg.

7.2 in Parallel with the dissolution of the sample, performing all operations of the methods and using the same quantities of reagents, carry out the blank experiment by dissolving pure iron.

7.3 Preparation of solutions

7.3.1 Preparation of the analyzed sample solution

A portion of the sample (7.1) is placed in a beaker with a capacity of 200 cm, add 10 cmof nitric acid (4.3), cover beaker watch glass and slowly heated until the cessation of the rapid evolution of gas. Add 10 cm of hydrochloric acid (4.2) and heating was continued until complete dissolution. Cooled to room temperature and transfer the solution into volumetric flask with a capacity of 200 cm. If you use the method of internal standard, then add 2cmof a solution of scandium (4.4) or 10 cmof a solution of yttrium (4.5). Bring the solution up to the mark with water and mix.

7.3.2 Preparation of calibration solutions

Conduct operations in accordance with ISO 13898−2, ISO 13898−3 and ISO 13898−4.

7.4 Spectrometer measurements

7.4.1 Include a spectrometer, and leave it on not less than one hour before any measurement.

Carry out calibration in the following parameters:

— adjust the flow rate of each gas stream (cooling, intermediate and discharge);

— the height of the photometry;

— the location of the input and output slits;

— the voltage on the photomultiplier tube;

— the wavelength of the analytical lines listed in table 2;

— washing time and the integration time, etc.

The adjustment is carried out in accordance with Annex And the introduction to the instrument calibration solution of higher concentration.

In the case of using the method with the use of internal standard prepare software for the use of a line of scandium (361,68 nm) or line of yttrium (371,03 nm) as internal standard to calculate the ratio of the intensity of the lines of each element and the intensity of the line scandium or yttrium.

The intensity of the line internal standard must be measured simultaneously with the intensity of the analytical line.

The performance requirements must comply with 5.1.1−5.1.3.

7.4.2 Measurement of radiation intensity

When measuring the absolute values of the intensities of the temperature of all solutions should not differ by more than 1 °C. All solutions should be filtered through filter paper medium density. The first 2−3 cmof the solutions discarded.

Carry out the measurement of the absolute or relative intensity of analytical line of the element, starting with the calibration solution.

Further measurements were carried out in the following order: measure two or three of the analyzed solution, calibration solution the minimum concentration, then two or more of the analyzed solutions, etc.

This procedure is the measurement of all analyte and calibration solution allows to minimize possible fluctuations in the intensity calibration and analyzed solutions in time.

For each solution carried out according to five dimensions. Assess short-term stability, which must conform to 5.1.1. Then, for each solution calculate the average intensity or the average intensity.

Subtract the values of the average absolute or average relative intensity of the zero solution of the values of the average absolute or average relative intensity of each solution , thus obtaining the values of the pure absolute or pure relative intensity

. (1)

7.4.3 Preparation of calibration curve

Build the schedule of dependence in coordinates: absolute or relative intensity;  — concentration of the element in the calibration solution (µg/cm).

Calculate the correlation coefficient. The correlation coefficient should meet the requirements specified in 5.1.3.

8 Determination of results

8.1 Processing of results

In accordance with the mathematical software of the spectrometer is carried out using a calibration curve (7.4.3) the transfer value of the absolute or relative intensity to the concentration of the element in the analyzed solution.

Mass fraction of element , %, is calculated by the formula

, (2)

where is the concentration of element in sample solution, µg/cm;

 — the concentration of the element in test solution, µg/cm;

 — the mass of sample, g;

 — the contents of the element in iron used, %.

8.2 Accuracy

To assess the accuracy of the methods provided in ISO 13898−2, ISO 13898−3, ISO 13898−4, was carried out interlaboratory tests on the samples are given in Appendix B.

9 test report

The test report must contain:

a) all information about the laboratory, date of test, identification of samples;

b) a reference to the method used in this standard;

c) test results;

d any operations not specified by this standard, or any additional operations that may affect the test results.

Annex a (informative). The method of determining the instrumental parameters

Appendix A
(reference)

A. 1 determination of the detection limit (DL), concentrations equivalent to background radiation (WEIGHT), and short-term stability

Development of standard analysis methods using atomic emission spectroscopy with inductively coupled plasma these criteria should be selected by the working group responsible for the results of interlaboratory tests.

Include a spectrometer and stand for some time to stabilize. Stabilization time can vary depending on the device. Under normal laboratory conditions of modern laboratory equipment should reach steady state in approximately 15 minutes. This can be verified in further tests the short-term stability using the tests indicated below.

Prepare three solution of the element corresponding to zero concentration, a concentration 10 times the detection limit (10хDL), and a concentration of 1000 times the detection limit (1000xDL).These solutions must contain the same acid concentrations, the same additional reagents and major elements as solutions of analyzed samples. The detection limits for these solutions can serve as a laboratory estimated or nominal characteristics of the method.

Solution concentration 1000хDL sprayed into the plasma for 10 s before measurements to ensure the stability of the dispersion.

Carefully choose the position, corresponding to the maximum peak at the selected wavelength, choose a suitable position of the photomultiplier (if this is not done automatically) to make sure that the intensity is measured with an accuracy to four significant digits. Set the integration time 3 s

A. 1.1 Definition of detection limit

The limits of detection can be determined by various methods depending on the type of device.

Can be recommended the following technique.

Spray the background the solution for about 10 s. Withdraw 10 readings at fixed integration time. Spray the solution concentration 10хDL for approximately 60 s. Remove the 10 readings at fixed integration time.

According to the intensity obtained for the background solution and the solution concentration 10хDL, calculates the average intensities and standard deviations of the background solution .

Calculate the average true intensity of the solution concentration 10xDL

. (A. 1)

By the formula below calculate the detection limit for the element

, (A. 2)

where is the concentration, µ g/cm, solution concentration 10xDL.

A. 1.2 determination of the concentration of equivalent background radiation

The concentration equivalent to the background radiation, calculated by the formula

. (A. 3)

A. 1.3 Definition of short-term stability

Spray the solution concentration 1000хDL for about 10 s. Record 10 readings at a predetermined integration time. Based on these data and data obtained for a solution concentration 10хDL, conduct respectively the calculation of the average true intensity , and and standard deviations and .

Expect short term stability of the emission signal at two levels of concentration

;

. (A. 4)

If there are multiple datasets, carry out the calculation of the values for each set.

The average value .

A. 2 calculation of the calibration curves

Determine the direct relationship that best describes the set of points (linear regression), which is reduced to finding the coefficients and in equation

, (A. 5)

where is the measured value of the absolute or relative intensities;

 — concentrations of calibration solutions.

This method is called the method of least squares. The slope of the obtained line and the point of intersection is determined by the following formulas:

; (A. 6)

, (A. 7)

where

;

,

where  — the average value of the concentration;

 — the average intensity value.

The correlation coefficient is determined by the formula

, (A. 8)

where .

Annex b (informative). The samples used in the interlaboratory tests

The App
(reference)

Table B. 1

Application (reference). Data on compliance with national standards of the Russian Federation the reference to international standards

Application
(reference)

Table C. 1