BS 6200-3 31 3-2002 Sampling and analysis of iron steel and other ferrous metals - Methods of analysis - Determination of tin - Flame atomic absorption spectrometric method (extrac.pdf

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1、BRITISH STANDARD BS 6200-3.31.3: 2002 ISO 15353:2001 Steel and iron Determination of tin content Flame atomic absorption spectrometric method (extraction as Sn-SCN) ICS 77.080.01 BS 6200-3.31.3:2002 This British Standard, having been prepared under the direction of the Engineering Sector Policy and

2、Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 11 October 2002 BSI 11 October 2002 ISBN 0 580 40426 9 National foreword This British Standard reproduces verbatim ISO 15353:2001 and implements it as the UK national standard. The UK participatio

3、n in its preparation was entrusted to Technical Committee ISE/18, Sampling and analysis of iron and steel, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement intern

4、ational publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to includ

5、e all the necessary provisions of a contract. Users are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enqui

6、ries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages 1 t

7、o 9 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsINTERNATIONAL STANDARD ISO 15353 First edition 2001-03-15 Reference number ISO 15353:2001(E) OSI 2001 Steel and iron Determin

8、ation of tin content Flame atomic absorption spectrometric method (extraction as Sn-SCN) Aciers et fontes Dosage de ltain Mthode par spectromtrie dabsorption atomique dans la flamme (extraction comme Sn-SCN) BS62003.31.3:2002BS62003.31.3:2002iiISO 53511002:3)E( ISO 1002 All rithgs rreseved iii Conte

9、nts Page 1 Scope . 1 2 Normative references . 1 3 Principle 1 4 Reagents 1 5 Apparatus . 3 6 Sampling . 3 7 Procedure . 4 8 Plotting the calibration graph 6 9 Expression of results 6 10 Test report 7 Annexes A Additional information on the international co-operative test 8 B Graphical representation

10、 of precision data . 9 BS62003.31.3:2002iiiISO :35351(1002)E vi ISO 1002 All rithgs rreseved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried

11、 out through ISO technical com- mittees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liai- son with ISO, also take part in the work.

12、 ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical comm

13、ittees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights.

14、ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 15353 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of determination of chemical composition. Annexes A and B of this International Standard are for informat

15、ion only. BS62003.31.3:2002ivANRETNIITOLAN TSDNADRA ISO 53511002:3)E( ISO 1002 All rithgs rreseved 1 Steel and iron Determination of tin content Flame atomic absorption spectrometric method (extraction as Sn-SCN) 1 Scope This International Standard specifies a method for the determination of tin in

16、steel and iron by means of flame atomic absorption spectrometry. The method is applicable to tin contents in the range by mass to by mass. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International St

17、andard. For dated references, subsequent amendments to, or revisions of, any of these publica- tions do not apply. However, parties to agreements based on this International Standard are encouraged to investi- gate the possibility of applying the most recent editions of the normative documents indic

18、ated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain reg- isters of currently valid International Standards. ISO 648:1977, Laboratory glassware One-mark pipettes. ISO 1042:1998, Laboratory glassware One-mark volumetric

19、flasks. ISO 3696:1987, Water for analytical laboratory use Specification and test methods. ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part 1: General prin- ciples and definitions. ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and

20、 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 measurement methods and results Part 3: Intermediate measures of the precision of a standard measurement method. ISO 14284:

21、1996, Steel and iron Sampling and preparation of samples for the determination of chemical composi- tion. 3 Principle Dissolution of a test portion in hydrochloric and nitric acids. Formation of Sn-SCN complex and extraction of the com- plex into 4-methyl-2-pentanone (isobutyl methyl ketone). Aspira

22、tion of the organic solution into a dinitrogen monoxide-acetylene flame. Spectrometric measurement of the atomic absorption of the spectral line emitted by a tin hollow cathode lamp. High purity tin metal dissolved as standard solution is used as reference material for calibration graphs. 4R e a g e

23、 n t s Use only reagents of recognized analytical grade, unless otherwise stated. 4.1 Water, complying with grade 2 as defined in ISO 3696. 0,001 % 0,1 % 224,6 nm BS62003.31.3:20021ISO :35351(1002)E 2 ISO 1002 All rithgs rreseved 4.2 Hydrochloric acid, HCl, approximately . 4.3 Hydrochloric acid, HCl

24、, diluted . 4.4 Nitric acid,HNO 3 , approximately . 4.5 Formic acid,HCO OH, a pp ro xim a tel y . 4.6 Hydrochloric acid, HCl, diluted . 4.7 Ascorbic acid,C 6 H 8 O 6 . 4.8 Potassium thiocyanate solution. Dissolve of potassium thiocyanate (KSCN) in water (4.1), dilute to and mix. Prepare the solution

25、 shortly before use. 4.9 4-methyl-2-pentanone (isobutyl methyl ketone),(CH 3 ) 2 CHCH 2 COCH 3 . 4.10 Washing solution. Dissolve of ascorbic acid (4.7) and of potassium thiocyanate in of hydrochloric acid (4.6). Prepare the solution shortly before use. 4.11 Tin, standard reference solution. 4.11.1 S

26、tock solution, corresponding to of tin per litre. Weigh, to the nearest , approximately of tin metal (minimum by mass). Transfer to a beaker and dissolve in of hydrochloric acid (4.2) and of nitric acid (4.4). Warm gently. Remove from the hot plate immediately after complete dissolution and allow to

27、 cool. Transfer the solution to a one-mark volumetric flask containing hydrochloric acid (4.2). Dilute to the mark with water and mix. of this stock solution contains of tin. 4.11.2 Standard reference solution A, corresponding to of tin per litre. Transfer of the stock solution (4.11.1) to a one-mar

28、k volumetric flask and add of hydrochloric acid (4.2). Dilute to the mark with water and mix. of this solution contains of tin. 4.11.3 Standard solution B, corresponding to of tin per litre. Transfer of the standard solution A (4.11.2) to a one-mark volumetric flask and add of hydrochlo- ric acid (4

29、.2). Dilute to the mark with water and mix. of this solution contains of tin. 4.12 Iron, free from tin (less than by mass). 4.13 Solution for optimization of the atomic absorption spectrometer. Dissolve of ascorbic acid (4.7) in of HCl (4.6). Allow to cool and add of the standard stock solution (4.1

30、1.1). Proceed exactly as specified in 7.3.2 but transfer the organic phase to a volumetric flask, dilute with 4-methyl-2-pentanone (4.9) to the mark and mix. The solution is stable for several weeks if the flask is properly closed. 1,19 g/ml 1 + 1 1,40 g/ml 1,21 g/ml 1 + 24 25 g 50 ml 45 g 25 g 500

31、ml 1g 0,000 1 mg 0,25 g 99,9 % 250 ml 20 ml 5 ml 250 ml 100 ml 1ml 1mg 50 mg 25 ml 500 ml 90 ml 1 ml 0,05 mg 5mg 25 ml 250 ml 50 ml 1 ml 0,005 mg 0,000 1 % 4 g 40 ml 3 ml 100 ml BS62003.31.3:20022ISO 53511002:3)E( ISO 1002 All rithgs rreseved 3 5A p p a r a t u s All volumetric glassware shall be gr

32、ade A, in accordance with ISO 648 or ISO 1042, as appropriate. Use ordinary laboratory apparatus. 5.1 Atomic absorption spectrometer, consisting of a tin hollow cathode lamp fuelled by supplies of acetylene and dinitrogen monoxide sufficiently pure to give a steady, clear, red-feather flame, free fr

33、om water and oil. The atomic absorption spectrometer used is deemed satisfactory if, after optimization according to 7.3.5, the limit of detection and characteristic concentration are in reasonable agreement with the values given by the manufacturer and if it meets the precision criteria given in 5.

34、1.1 to 5.1.3. It is also desirable that the instrument conform to the ad- ditional performance requirement given in 5.1.4. 5.1.1 Short term stability The standard deviation of ten measurements of the absorbance of the most concentrated calibration solution shall not exceed of the mean absorbance of

35、the same solution. 5.1.2 Limit of detection This is determined by taking three times the standard deviation of ten measurements of the absorbance of a solution containing the appropriate element at a concentration level selected to give an absorbance just above that of the zero member. The limit of

36、detection of tin in a matrix similar to the final test portion solution shall be better than oftinino rg an i cso lu tio n . 5.1.3 Graph linearity The slope of the calibration graph covering the top of the concentration range (expressed as a change in ab- sorbancy) shall be not less than 0,7 times t

37、he value of the slope for the bottom of the concentration range de- termined in the same way. For instruments with automatic calibration using two or more standards, it shall be established prior to the analysis, by obtaining absorbance readings, that the above requirements for graph linearity are f

38、ulfilled. 5.1.4 Characteristic concentration The characteristic concentration for tin in a matrix similar to the final test portion solution shall be better than of tin in organic solution. 5.2 Ancillary equipment, consisting of a strip chart recorder and/or digital readout device recommended to eva

39、lu- ate the criteria listed for 5.1 and for all subsequent measurements. Scale expansion can be used until the noise observed is greater than the readout error and is always recommended for absorbances below 0,1. If scale expansion has to be used and the instrument does not have the means to read th

40、e value of the scale expansion factor, the value can be calculated by measuring a suitable solution with and without scale expansion and simply dividing the signal obtained. 6 Sampling Carry out sampling in accordance with ISO 14284 or appropriate national standards for steel. 1,5 % 0,1 g/ml 20 % 20

41、 % 0,4 g/ml BS62003.31.3:20023ISO :35351(1002)E 4 ISO 1002 All rithgs rreseved 7 Procedure 7.1 Test portion Weigh, to the nearest , a test portion of the sample according to Table 1. 7.2 Blank test In parallel with the determination and following the same procedure, carry out a blank test using the

42、same quantities of all the reagents but omitting the test portion. 7.3 Determination 7.3.1 Preparation of the test solution Place the test portion (see 7.1) in a beaker. Add of hydrochloric acid (4.3) and of nitric acid (4.4) then cover the beaker. Heat gently. After complete dissolution, immediatel

43、y remove the beaker from the hot plate and allow to cool. Rinse the lid with water and add of formic acid (4.5). Heat gently (without lid) until the reaction has ceased, then immediately remove the beaker from the hot plate. Dilute with of hydrochloric acid (4.6). Add of ascorbic acid (4.7) and diss

44、olve by gentle heating. Remove immediately from the hot plate and cool to am- bient temperature. 7.3.2 Extraction Transfer the sample solution quantitatively to a separating funnel and dilute with hydrochloric acid (4.6) to . Add potassium thiocyanate solution (4.8) and 4-methyl-2-pentanone (4.9). S

45、hake vigorously for . Let the phases separate completely. This normally takes approximately , but in the case of samples containing graphite, or elements that precipitate, it may take up to to . Discard the lower aqueous phase. Add of washing solution (4.10). Shake vigorously for . Let the phases se

46、parate completely. Discard the lower aqueous phase. It is not necessary to separate the organic phase quantitatively. Discard approximately of this together with the aqueous phase. Make sure that all water is removed from the stem of the separation funnel. Filter the organic phase through a dry rapi

47、d filter paper into a dry volumetric flask. Close the flask. The solution is stable for . Table 1 Test portions Expected tin content Test portion by mass g 0,001 to 0,025 1 0,025 to 0,05 0,5 0,05 to 0,1 0,25 0,000 1 g % 250 ml 20 ml 5 ml 5ml 20 ml 4g 125 ml 60 ml 5 ml 10 ml 60 s 5 min 15 min 20 min

48、50 ml 120 s 0,5 ml 10 ml 24 h BS62003.31.3:20024ISO 53511002:3)E( ISO 1002 All rithgs rreseved 5 7.3.3 Preparation of the calibration solutions Introduce into a series of six beakers, iron (4.12) and tin standard solutions (4.11.2 and 4.11.3) as indicated in Table 2. Proceed exactly as specified in

49、7.3.1 and 7.3.2. 7.3.4 Adjustment of the atomic absorption spectrometer Proceed as specified in Table 3. 7.3.5 Optimization of the atomic absorption spectrometer settings Follow the manufacturers instructions for preparation of the instrument for use. When this is done, aspirate 4-methyl- 2-pentanone (4.9). Adjust the instrument to give maximum signal while aspirating the optimization solution (4.13). Continue to aspirate 4-me