GOST R ISO 15353-2014

• gost-r-iso-15353-2014.pdf (469.47 KiB)
  ГОСТ Р ИСО 15353-2014

GOST R ISO 15353−2014 Steel and cast iron. Determination of tin. Spectrometric method of atomic absorption in flame (extraction in Sn-SCN)

GOST R ISO 15353−2014

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

STEEL AND CAST IRON

Determination of tin. Spectrometric method of atomic absorption in flame (extraction in Sn-SCN)

Steel and iron — Determination of tin content — Flame atomic absorption spectrometric method (extraction as Sn-SCN)

OKS 77.080.20*
AXTU 0709

______________
* According to the official website of Rosstandart
OKS 77.080.01. — Note the manufacturer’s database.

Date of introduction 2015−01−01

Preface

1 PREPARED by the Federal state unitary enterprise «Central scientific research Institute im.And.P.Bardin," on the basis of their own authentic translation into the Russian language of the standard referred to in paragraph 4

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

3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology of June 11, 2014 N 648-St

4 this standard is identical to international standard ISO 15353:2001* «Steel and cast iron. Determination of tin. Spectrometric method of atomic absorption in flame (extraction in Sn-SCN)» (ISO 15353:2001 «Steel and iron — Determination of tin content — Flame atomic absorption spectrometric method (extraction as Sn-SCN)»).
________________
* Access to international and foreign documents referred to here and hereinafter, can be obtained by clicking on the link to the site shop.cntd.ru. — Note the manufacturer’s database.


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

5 INTRODUCED FOR THE FIRST TIME


Application rules of this standard are established in GOST R 1.0−2012 (section 8). Information about the changes to this standard is published in the annual (as of January 1 of the current year) reference index «National standards» and the official text changes and amendments — in monthly information index «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in a future issue of 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 (gost.ru)

1 Scope

This standard specifies the flame atomic absorption spectrometric method for the determination of tin in steel and iron.

The method is applicable for determining the mass fraction of tin in the range of 0.001% to 0.1%.

2 Normative references

The present standard features references to the following standards*:
________________
* The table of conformity of national standards international see the link. — Note the manufacturer’s database.


ISO 648:1977 laboratory Glassware glass. Pipettes with one mark (ISO 648:1977, Laboratory glassware — One-mark pipettes)

ISO 1042:1998 laboratory Glassware glass. Flasks volumetric with one mark (ISO 1042:1998, Laboratory glassware — One-mark volumetric flasks)

ISO 3696:1987 Water for analytical use in the laboratory — specifications and test methods (ISO 3696:1987, Water for analytical laboratory use — Specification and test methods)

ISO 5725−1:1994 Accuracy (trueness and precision) of methods and measurement results — Part 1: General provisions and definitions (ISO 5725−1:1994, Accuracy (trueness and precision) of measurement methods and results — Part 1: General principles and definitions)

ISO 5725−2:1994 Accuracy (trueness and precision) of methods and measurement results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method (ISO 5725−2:1994, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method)

ISO 5725−3:1994 Accuracy (trueness and precision) of methods and measurement results — Part 3: Intermediate indicators of the precision of a standard measurement method (ISO 5725−3:1994, Accuracy (trueness and precision) of measurement methods and results — Part 3: Intermediate measures of the precision of a standard measurement method)

ISO 14284:1996 Steel and iron. Selection and preparation of samples for the determination of chemical composition (ISO 14284:1996, Steel and iron — Sampling and preparation of samples for the determination of the chemical composition)

3 the essence of the method

This method is based on dissolving a measured sample in hydrochloric and nitric acids, the formation of Sn-SCN-complex and the extraction of the complex in 4-methyl-2-pentanon (isobutyl methylketone).

The obtained organic solution is sprayed into the flame denitrated-acetylene and perform a spectrometric measurement of the absorption values of the radiation emitted by the lamp with hollow cathode for tin, free tin atoms at a wavelength of 543 nm.

4 Reagents

In the analysis, unless otherwise stated, use only reagents established analytical purity.

4.1 Unless otherwise specified, use distilled water, further purified by distillation or other means.

4.2 Hydrochloric acid (), 1,19 g/cm.

4.3 Hydrochloric acid, diluted 1:1.

4.4 Nitric acid (), of 1.40 g/cm.

4.5 Formic acid (a), of 1.21 g/cm.

4.6 Hydrochloric acid (in), diluted 1:24.

4.7 Ascorbic acid ().

4.8 Potassium rodanistye, solution.

25 g of potassium Rodenstock () dissolved in distilled water (4.1), dilute to 50 cmand mixed. The solution is prepared immediately before use.

4.9 4-methyl-2-pentanon (isobutyl methyl ketone), .

4.10 Wash solution.

45 g of ascorbic acid (4.7) and 25 g of potassium Rodenstock dissolved in 500 cmof hydrochloric acid (4.6). The solution is prepared immediately before use.

4.11 Lead, standard solution

4.11.1 Basic solution containing 1 g/DMof tin.

Weighed (accuracy of 0.0001 mg) of 0.25 g of tin metal, with a mass fraction of tin is not less than 99.9%. Put a portion into a glass with a capacity of 250 cmand dissolve with a moderate heat, in 20 cmof hydrochloric acid (4.2) and 5 cmof nitric acid (4.4). Immediately remove the beaker from the hot plate after complete dissolution of the tin and leave to cool solution. Quantitatively transfer the solution into volumetric flask with one mark capacity of 250 cm, containing 100 cmof hydrochloric acid (4.2). Dilute to the mark with water and mix the solution.

1 cmthis basic solution contains 1 mg of tin.

4.11.2 Standard solution containing 50 mg/ ltin.

Stand 25 cmbasic solution (4.11.1) volumetric flask with one mark capacity of 500 cmand 90 cm addhydrochloric acid (4.2). The solution was diluted to the mark with water and mix.

1 cmof this standard solution contains 0.05 mg of tin.

4.11.3 Standard solution containing 5 mg/ltin.

Placed 25 cmstandard solution A (4.11.2) in a volumetric flask with one mark capacity of 250 cmand add 50 cmof hydrochloric acid (4.2). The solution was diluted to the mark with water and mix.

1 cmof this solution contains 0.005 mg of tin.

4.12 the Iron containing tin (valid less than 0.0001% tin).

4.13 Solution to optimize the operation of atomic absorption spectrometer.

4 g of ascorbic acid (4.7) is dissolved in 40 cmof hydrochloric acid (4.6). To the cooled solution was added 3 cmof the primary standard solution of tin (4.11.1). Performs operations in strict accordance with 7.3.2, but the organic phase is placed in a volumetric flask with a capacity of 100 cm, is diluted to the mark 4-methyl-2-pentanone (4.9) and mix. The solution remains stable for several weeks if the bulb is securely closed.

5 Instrument

All volumetric glassware should be class A in accordance with ISO 648 ISO 1042 or, depending on what is required.

Use conventional laboratory equipment and the following equipment.

5.1 Atomic absorption spectrometer, equipped with a lamp with a hollow cathode for tin, stocks of acetylene and denitrated that do not contain oil water and clean enough to form a stable pure red flame.

Atomic absorption spectrometer is considered suitable for use if after the optimization mode 7.3.5 values of limit of detection and characteristic concentration will correspond to the values specified by the instrument manufacturer and precision criteria established in 5.1.1−5.1.3. In addition, it is desirable that the device meets the additional requirements specified in 5.1.4

5.1.1 minimum (short-term) stability

The standard deviation of the 10 values of absorbance of the most concentrated calibration solution should not exceed 1.5% of the average absorption of the solution.

5.1.2 detection Limit

The detection limit calculated as three times the standard deviation of the 10 values of the absorption solution containing the corresponding element with a selected concentration level with a value of absorption is slightly higher than the zero solution. The detection limit of tin in the matrix is similar to the final analyzed sample solution of the sample should be less than 0.1 mg/cmtin in organic solution.

5.1.3 linearity of calibration curve

The slope of the calibration curve for the top 20% of the concentration region (expressed as change in absorbance) should not be less than 0.7 the values of slope for the bottom 20% of the concentration region that is defined in the same way. For instruments with automatic calibration to get the readings of absorption using 2 or more standards, with the above linearity requirements of the schedule should run.

5.1.4 Characteristic concentration

The characteristic concentration of tin in the matrix, similar to the final analyzed sample solution of the sample should be less than 0.4 mg/cmtin in organic solution.

5.2 accessories

For assessment criteria 5.1 and to all subsequent measurements, use a tape recorder and (or) digital reader.

The extension of the scale can be used as long as the observed noise does not exceed the error of the reader and it is always recommended to use when the values of absorbance below 0.1. If you want to use the extension scale, and the instrument has no device for determining the expansion factor of the scale, this value can be calculated by simple division of the values of absorption corresponding solution obtained with extension and without extension of the scale.

6 Sampling

Sampling carried out in accordance with ISO 14284 or other appropriate national standards for steel.

7 analysis

7.1 Analytical linkage

The analytical sample is weighed in accordance with the data of table 1 with an accuracy close to 0,0001 g.

Table 1 — Analytical linkage

7.2 Blank

In parallel with the analysis of the investigated samples is carried out blank. A blank experiment is performed under the same conditions using the same technique, the same amounts of all the necessary reagents excluding the sample of a measured sample.

7.3 Definition

7.3.1 Preparation of test solution

The linkage of a measured sample (7.1) is placed in a beaker with a capacity of 250 cm, add 20 cmof hydrochloric acid (4.3) and 5 cmof nitric acid (4.4), cover with the glass lid and gently warmed. After complete dissolution of the sample, the glass is immediately removed from the hot plate and cool the solution. Wash the cover with water and add 5 cmof formic acid (4.5). Gently heat the Cup (without a lid) until the termination of the reaction, then the glass is immediately removed from the hot plate and dilute the solution to 20 cmof hydrochloric acid (4.6). Add 4 g of ascorbic acid (4.7) and dissolve with a moderate heat. Once dissolved, immediately remove the beaker from the hot plate and cooled to room temperature.

7.3.2 Extraction

The sample solution is quantitatively transferred to a separating funnel with a capacity of 125 cmand dilute hydrochloric acid (4.6) to 60 cm. Add 5 cmof a solution of potassium Rodenstock (4.8) and 10 cm4-methyl-2-pentanone (isobutyl methyl ketone) (4.9). Shake the funnel vigorously for 60 s. allow the phases to separate completely, this is normally 5 minutes, but in the case of samples containing graphite, or elements, drop down into the sediment, the process may last from 15 min to 20 min. the Aqueous phase is discarded. Add 50 cmwash solution (4.10) and shake the funnel vigorously for 120 s. allow the phases to separate completely, the aqueous phase is discarded. There is no need to quantitatively separate the organic phase. Drop approximately 0.5 cmof a solution containing both phases. Be sure to remove all the water from the barrel of a separating funnel. The organic phase is filtered through a dry filter fast filter paper in a dry volumetric flask with a capacity of 10 cm. The flask is closed. The solution is stable for 24 hours.

7.3.3 Preparation of the calibration solutions

A series of 6 cups capacity 250 cmmake iron (4.12) and standard solutions of tin (4.11.2 and 4.11.3) in accordance with table 2. Operations are performed exactly in accordance with 7.3.1 and 7.3.2.

Table 2 — Calibration solutions

7.3.4 setup of atomic absorption spectrometer

The parameters are given in table 3.

7.3.5 optimization of the mode of operation of the atomic absorption spectrometer.

You must follow the recommendations of the manufacturer when preparing the appliance for use. When that is shown, the spray 4-methyl-2-pentanone (4.9). Device adjust until you get maximum signal when sprayed on optimization solution (4.13). Continue spraying 4-methyl-2-pentanone (4.9), until you are sure that the instrument is ready for measurement. Appreciate the instrumental criteria (5.1.1−5.1.3) and additional characteristics, 5.1.4, to ensure that the device is ready for measurement.

Table 3 Instrumental parameters

7.3.6 Spectrometric measurements

The absorbance measurement starting with the spraying of the least concentrated calibration solution. Then continue the measurement of two or three solutions of analyzed samples with unknown content of tin, then the following (in ascending order) calibration solution, two or more of the solution analyzed samples with an unknown amount of tin, etc. Thus, all solutions analyzed unknown samples will be measured in the same period of time, and calibration solutions. This measurement procedure eliminates the possibility of instrument drift between measurements of the calibration solutions and the unknown solutions are analyzed.

8 Construction of calibration curve

You need to build a separate calibration curve for each measurement series. When using pure metals and reagents to zero the solution should give the insignificant small indications of absorption, is not taken into account because of the small difference. In this case, build a calibration curve, plotting the average absorbance of the calibration solutions on the coordinate axes about the content in µg/cmof tin in solutions. If the zero solution has a significant absorption, it requires a more complete procedure. In this case, the mass of tin in the zero solution is calculated by the formula

,

where  — weight of tin, in micrograms, added to the first calibration solution;

 — the value of zero absorption of the solution;

the value of absorption of the first calibration solution.

The set value is added to each nominal mass calibration to obtain a calibration curve passing through the origin.

9 processing of the results

9.1 Calculation method

The tin content found by the calibration graphic in the blank solution experience (7.2) and analyze solutions, using the measured values of absorbance of these solutions. The tin content found in the blank solution experience, is subtracted from the results of analyzed solutions.

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

,

where the tin content, µg in the sample solution, was found in the calibration chart;

 — the weight of the portion of the sample,

9.2 Precision

Planned testing of this method was performed in ten laboratories in nine levels of contents of tin, each laboratory carried out three for the determination of tin (see notes 1 and 2) for each level.

The samples used are listed in table A. 1.

The obtained results were processed statistically in accordance with the requirements of standards ISO 5725−1, ISO 5725−2 and ISO 5725−3.

The data show a logarithmic dependence between the content of tin, repeatability (), reproducibility (and ) and test results, as summarized in table 4. Graphical representation of the data shown in figure B. 1.

Table 4 — Repeatability and reproducibility

10 test report

The test report must contain:

— all information necessary for sample identification, laboratory and data analysis;

— used the method with reference to ISO 15353;

the results and the form in which they are presented;

— features observed during the analysis;

— operations not specified by this standard, or any optional operations that may affect the results of the analysis.

Annex a (informative). Additional information for international test

Appendix A
(reference)

Table 4 shows the results of the international analytical tests carried out in 1994−1996 in nine samples of steel in the six countries carried out in ten laboratories.

Test results were reported in document ISO/TC 17/SC 1 N 1147. Graphical representation of precision data are given in Appendix B.

The samples used in the tests are shown in table A. 1.

Table A. 1 — test specimens

Annex b (informative). Graphical representation of precision data

The App
(reference)

Figure B. 1 — Graphical representation of precision data

 — 2,0373

 — 1,7239

 — 1,555

Figure B. 1 — Graphical representation of precision data

App YES (reference). Information about the compliance of the referenced international standards national standards of the Russian Federation (and acting in this capacity inter-state standards)

App YES
(reference)

Table YES.1

_____________________________________________________________________

UDC 669.14:620.2:006.354 OKS 77.080.20 AXTU 0709

Keywords: steel, determination of tin, spectrometric atomic absorption method