BS 6200-3 16 4-1987 Sampling and analysis of iron steel and other ferrous metals - Methods of analysis - Determination of lead - Steel flame atomic absorption spectrometric method《.pdf

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1、BRITISH STANDARD BS 6200-3.16.4: 1987 EN 10181:1989 EU 181:1985 Incorporating Amendment No. 1 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.16 Determination of lead Subsection 3.16.4 Steel: flame atomic absorption spectrometric method EU title: C

2、hemical analysis of ferrous materials. Determination of lead in steels Flame atomic absorption spectrometric method The European Standard EN 10181:1989 has the status of a British Standard UDC 543:422:546.815:669.14BS6200-3.16.4:1987 This British Standard, having been prepared under the directionof

3、the Iron and Steel Standards Committee, was published under the authority ofthe Board of BSI and comes into effect on 31July 1987 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Draft announced in BSI News December 1985 ISBN 0 580 15981 7 Nati

4、onal foreword This Subsection of BS 6200 has been prepared under the direction of the Iron and Steel Standards Committee. It is identical with Euronorm 181:1985 “Chemical analysis of ferrous materials. Determination of lead in steel. Flame atomic absorption spectrometric method” published by the Com

5、mission of the European Communities. In 1989 the European Committee for Standardization (CEN) accepted EU181:1985 as European Standard EN 10181:1989. Cross-reference. The Technical Committee has reviewed the provisions of Euronorm 18, to which reference is made in clause 6, and has decided that they

6、 are acceptable for use in conjunction with this standard. At present there is no corresponding British Standard for Euronorm 18. Appropriate procedures from Euronorm 18 will be incorporated in BS 6200-2 “Methods of sampling and sample preparation”, which will be published in due course. Additional

7、information. The method given embodies an early practice of subtracting the absorbance of the zero calibration solution from the absorbances of the other calibration solutions to obtain the net absorbances which are used in the preparation of the graph. This is a potential source of error in methods

8、 where there is a significant amount of analyte in the base metal and the calibration graph is non-linear. Tests have shown, however, that if curvature is limited such that the slope of the calibration graph covering the top20% of the concentration range (expressed as a change in absorbance) is not

9、less than 0.7times the slope of the bottom 20% concentration range determined in the same way, and the concentration of lead in the iron base metal is not greater than 0.001% Pb as required in the method, the error will be less than 0.001% Pb at the 0.5 % Pb level. Details of the procedures to be ad

10、opted in methods where these restrictions do not apply will be included in BS 6200-6, to be published in due course. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a

11、British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theENtitlepage, pages2 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have

12、 had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue Comments 7072 February 1992 Indicated by a sideline in the marginBS6200-3.16.4:1987 BSI 09-1999 i Contents Page National foreword Inside f

13、ront cover Brief history 2 1 Scope and field of application 3 2 Reference 3 3 Principle 3 4 Reagents 3 5 Apparatus 3 6 Sampling 3 7 Procedure 4 8 Expression of results 5 9 Test report 5 Annex 6 Publications referred to Inside back coverii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 101

14、81 January 1989 UDC 543.422:546.815:669.14 Descriptors: Iron and steel products, steels, chemical analysis, determination of content, lead, atomic absorption spectrometry, flamephotometry English version Chemical analysis of ferrous materials Determination of lead in steels Flame atomic absorption s

15、pectrometric method Analyse chimique des matriaux sidrurgiques Dosage du plomb dans les aciers Mthode par spectromtrie dabsorption atomique dans laflamme Chemische Analyse von Eisen und Stahlwerkstoffen Bestimmung des Bleigehaltes von Stahl Flammenatomabsorptions spektrometrisches Verfahren This Eur

16、opean Standard was approved by CEN on 1989-01-15. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references conce

17、rning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own

18、language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards organizations of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switz

19、erland and United Kingdom CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels CEN 1989 Copyright reserved to all CEN members Ref. No. EN 10181:1989 EEN10181:1989 BSI 09-1999 2 Brief history

20、This European Standard takes over the content of EURONORM 181-85 “Chemical analysis of ferrous materials Determination of lead in steels Flame atomic absorption spectrometric method”, prepared by ECISS/TC 20 “Methods of chemical analysis”, the Secretariat of which is allocated to the Dansk Standardi

21、seringsrad (DS). It has been submitted to the CEN Formal Vote following the decision of the Coordinating Commission (COCOR) of the European Committee for Iron and Steel Standardization on 1987-11-24/25. It has been adopted and ratified by CEN BT on1988-11-05. According to the Common CEN/CENELEC Rule

22、s, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. Note in clauses1 and9 EURONORM shall read EUROPEAN

23、STANDARD.EN10181:1989 BSI 09-1999 3 1 Scope and field of application This EURONORM specifies a method for the determination of lead in steels by means of flame atomic absorption spectrometry. The method is applicable to non-alloy and low-alloy steels with lead contents of 0.003 to 0.5% (m/m) (seeAnn

24、ex). 2 Reference EURONORM 18 Selection and preparation of samples and test pieces for steel and iron and steel products. General guidelines for the application of flame atomic absorption spectrometric methods are in course of preparation. 3 Principle Dissolution of a test portion with hydrochloric a

25、cid followed by oxidation with nitric acid. Spraying of the solution into an air-acetylene flame. Determination of the lead by means of the spectrometric measurement of the atomic absorption of the 283.3nm line emitted by a lead radiation source. The instrument is calibrated by addition of a lead st

26、andard solution to a similar matrix to that of the test solution. 4 Reagents During the analysis use only reagents of recognized analytical reagent quality and having a very low lead content, and only distilled water or water of equivalent purity. Carefully check the lead content of all reagents. If

27、 possible, use only freshly prepared distilled or deionized water. 4.1 Iron, of high purity, with a lead content0.001% (m/m) 4.2 Hydrochloric acid, 1.19 g/ml approximately, diluted 1 + 1 (V/V) (6 mol/l approximately) 4.3 Nitric acid, 1.40 g/ml approximately, diluted4+ 6 (V/V), (5.6 mol/l approximate

28、ly) 4.4 Lead reference solution corresponding to 0.5mg of lead per ml Wash approximately 1 g of lead (W 99.9% pure) in boiling hydrochloric acid 1.19 g/ml, diluted1+7(V/V) and afterwards with water and acetone. Dry the lead in a vacuum desiccator. Weigh, to the nearest 0.001 g, approximately 0.5 g o

29、f the purified lead. Transfer the weighed mass to a400 ml beaker and dissolve in 25 ml nitric acid 1.40 g/ml approximately, diluted 1 + 4 (V/V) by heating. Boil the solution to remove oxides of nitrogen, cool and transfer the solution to a 1000 ml volumetric flask, dilute to the mark with water and

30、mix. Calculate the concentration of lead, in mg/ml. 5 Apparatus Ordinary laboratory equipment and 5.1 Atomic absorption spectrometer; a lead radiation source; supplies of air and acetylene sufficiently pure to give a clear fuel-lean flame, free from water and oil, and free from lead The atomic absor

31、ption spectrometer used will be satisfactory if after optimization according to7.3.4 the limit of detection and characteristic concentration are in reasonable agreement with the values given by the manufacturer and it meets the following performance requirements. 5.1.1 Minimum precision The standard

32、 deviation of 10 measurements of the absorbance of the most concentrated calibration solution shall not exceed 1.5% of the mean absorbance. The standard deviation of 10 measurements of the absorbance of the least concentrated calibration solution (excluding the zero calibration solution) shall not e

33、xceed 0.5% of the mean absorbance of the most concentrated calibration solution. For example, if the top and bottom calibration solutions represent 0.50% and 0.05% lead in the sample, the precision called for (as two standard deviations) would be 0.015% and 0.005% lead respectively, assuming curve l

34、inearity. 5.1.2 Additional performance requirements It is also desirable that the instrument should conform to the following additional performance requirements. a) Characteristic concentration. The characteristic concentration for lead in a matrix similar to the final test solution shall be better

35、than 0.6 g/ml. b) Limit of detection. The limit of detection of lead in a matrix similar to the final sample test solution shall be better than 0.3g/ml. 5.2 Ancillary equipment A strip chart recorder and/or digital readout device is recommended to evaluate the criteria in5.1 and for all subsequent m

36、easurements. 6 Sampling Sampling shall be carried out in accordance with EURONORM 18.EN10181:1989 4 BSI 09-1999 7 Procedure 7.1 Test portion Weigh the mass (m) indicated below to the nearest0.001 g: m = 2g 5%. 7.2 Blank test With each analytical run, carry out an analysis on a reagent blank in paral

37、lel with the test portion analysis, using identical reagents, conditions, analytical procedures and dilutions throughout. 7.3 Determination 7.3.1 Preparation of the test solution Place the test portion (7.1) in a 250 ml beaker. Add30 ml of hydrochloric acid (4.2). Heat gently until the reaction ceas

38、es. Oxidize with5ml nitric acid (4.3). Boil the solution for 5 minutes to remove oxides of nitrogen. Cool, transfer the solution to a100ml volumetric flask, dilute to the mark with water and mix. If a residue has been left in the solution, filter off a portion through a dry medium textured filter pa

39、per, discarding the first runnings. 7.3.2 Preparation of the calibration solutions Place 10 g of iron (4.1) in an 800ml beaker and add100ml of hydrochloric acid (4.2). Heat gently until the reaction ceases. Oxidize with 20 ml of nitric acid(4.3). Boil the solution for5minutes to remove oxides of nit

40、rogen. Transfer to a250ml volumetric flask, dilute to the mark with water and mix. Transfer a series of 25.0 ml aliquots to 50 ml volumetric flasks. Add, by means of a burette or pipette, respectively 0; 1.0; 2.0; 3.0; 4.0; 5.0; 6.0; 8.0 and 10.0 ml of the lead reference solution (4.4), dilute to th

41、e mark with water and mix. NOTE1 ml of lead reference solution (4.4) is equivalent to approximately 0.05% (m/m) in the sample. 7.3.3 Adjustment of atomic absorption spectrometer (5.1) NOTEThe manufacturers recommendations should be closely followed and particular attention is drawn to the following

42、safety points: a) the explosive nature of acetylene, and regulations concerning its use; b) the need to shield the eyes of the operator from u.v. radiation by means of tinted glass; c) the need to keep the burner head clear of deposits. A badly clogged burner may cause a flash back. d) make sure tha

43、t the liquid trap is filled with water. 7.3.4 Optimization of the atomic absorption spectrometer settings Follow the manufacturers instructions for preparing the instrument for use. When the current to the lamp, the wavelength and the flow of gas have been adjusted and the burner lit, spray water un

44、til the indication has stabilized. Set the absorbance value to zero. Choose a damping setting or integration time to give a signal steady enough to fulfil the precision requirements (5.1.1). Adjust the flame to be clear fuel-lean and the burner height to about 1cm below the light path. Spraying, alt

45、ernately, the high and zero calibration solutions, adjust the gas flow and burner position (horizontally, vertically and rotationally) until the difference in absorbance between the calibration solutions is at a maximum. Evaluate the criteria of5.1.1 to ensure that the instrument is suitable for the

46、 determination. 7.3.5 Atomic absorption measurements Set the scale expansion so that the top calibration solution gives nearly full scale deflection. Aspirate the calibration solutions in ascending order repetitively until each gives the acceptable precision (see5.1.1), thus showing that the instrum

47、ent has achieved stability. Select two calibration solutions, one having an absorbance just lower than the test solution and one just higher. Aspirate these first in ascending order, then in descending order, with the test solution as the middle solution in each case measuring the absorbance in rela

48、tion to water. Aspirate the complete range of calibration solutions again. It is recognized that these procedures cannot be followed with automatic instruments which accept two calibration solutions only. In this case it is suggested that the two “sandwiching” solutions should not be used for the pr

49、imary calibration but should be analysed alternately with the test solution. Obtain the net mean absorbance of each calibration solution by subtracting the mean absorbance of the zero calibration solution. Obtain the mean absorbance of the test solution and the mean absorbance of the reagent blank solution. Convert the mean absorbances of the test solution and of the reagent blank solution to micrograms of lead per millilitre by means of the calibration graph(7.4). Type of lamp: Wavelength: Flame: Lead radiation source. 283.3