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1、BRITISH STANDARD BS ISO 11438-1:1993 Implementation of ISO 11438-1:1993 Ferronickel Determination of trace-element content by electrothermal atomic absorption spectrometric method Part 1: General requirements and sample dissolution UDC 669.245:543.422.064 BS ISO 11438-1:1993 This British Standard, h
2、aving been prepared under the direction of the Non-ferrous Metals Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 May 1994 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference NFM/10 Draft f
3、or comment 92/42086 DC ISBN 0 580 23351 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Non-ferrous Metals Standards Policy Committee (NFM/-) to Technical Committee NFM/10, upon which the following bodies were represented: Association
4、of Bronze and Brass Founders British Non-ferrous Metals Federation British Stainless Steel Association British Steel Industry Department of Trade and Industry (Laboratory of the Government Chemist) Engineering Equipment and Materials Users Association Institute of British Foundrymen London Metal Exc
5、hange Ministry of Defence Nickel Development Institute Non-ferrous Metal Stockists Steel Casting Research and Trade Association Coopted members Amendments issued since publication Amd. No.DateComments BS ISO 11438-1:1993 BSI 02-2000i Contents Page Committees responsibleInside front cover National fo
6、rewordii Forewordiii Text of ISO 11438-11 BS ISO 11438-1:1993 ii BSI 02-2000 National foreword This British Standard reproduces verbatim ISO 11438-1:1993 and implements it as the UK national standard. This British Standard is published under the direction of the Non-ferrous Metals Standards Policy C
7、ommittee whose Technical Committee NFM/10 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developme
8、nts and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, Publications, BSI, Linford Wood, Milton Keynes, MK14 6LE. A British Standard does not purport to include all the necessary provisions of a contract. Users
9、 of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages
10、1 to 5 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. ISO 11438-1:1993(E) ii BSI 02-2000 Contents Page Forewordiii Introduction1 1Scope1 2Normative references1 3P
11、rinciple1 4Reagents1 5Apparatus1 6Sampling and sample preparation2 7Procedure2 8Expression of results3 9Note on procedure5 10Test report5 Figure 1 Graph of semi-quantitative standard additions3 Figure 2 Quantitative standard additions plot4 ISO 11438-1:1993(E) BSI 02-2000iii Foreword ISO (the Intern
12、ational Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has b
13、een established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical sta
14、ndardization. Draft International Standards adopted by the technical committees 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. International Standard ISO 11438-1 was prepared by Technica
15、l Committee ISO/TC 155, Nickel and nickel alloys, Sub-Committee SC 3, Analysis of nickel and ferronickel. ISO 11438 consists of the following parts, under the general title Ferronickel Determination of trace-element content by electrothermal atomic absorption spectrometric method: Part 1: General re
16、quirements and sample dissolution; Part 2: Determination of lead content; Part 3: Determination of antimony content; Part 4: Determination of tin content; Part 5: Determination of tellurium content; Part 6: Determination of thallium content; Part 7: Determination of silver content; Part 8: Determina
17、tion of indium content. iv blank ISO 11438-1:1993(E) BSI 02-20001 Introduction This part of ISO 11438 is to be used in conjunction with the other parts which specify methods for the determination of individual trace elements in ferronickel by electrothermal atomic absorption spectrometry, according
18、to the principle of standard additions. Although the analytical methods are in independent International Standards it is possible to determine more than one element on a single test solution. 1 Scope 1.1 ISO 11438 specifies electrothermal atomic absorption methods for the determination of trace elem
19、ents in ferronickel, in the specific concentration ranges shown in clause 1 of parts 2 to 8. For each element, the range of contents, in grams per tonne (g/t), corresponds to the linear part of the calibration graph of the standard additions for which the procedure may be used. 1.2 This part of ISO
20、11438 specifies the general requirements for analysis by electrothermal atomic absorption spectrometry, preparation and dissolution of the test sample, general procedure, method of calculation and the procedures used for the evaluation of the repeatability and reproducibility of the individual metho
21、ds specified in the other parts of ISO 11438. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 11438. At the time of publication, the editions indicated were valid. All standards are subject to revision
22、, and parties to agreements based on this part of ISO 11438 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 648:1977, Laboratory glassware On
23、e-mark pipettes. ISO 1042:1983, Laboratory glassware One-mark volumetric flasks. ISO 3696:1987, Water for analytical laboratory use Specification and test methods. ISO 5725:1986, Precision of test methods Determination of repeatability and reproducibility for a standard test method by inter-laborato
24、ry tests. ISO 8050:1988, Ferronickel ingots or pieces Sampling for analysis. 3 Principle Dissolution of a test portion in dilute nitric acid. Dilution of the test solution to a known volume and injection of a small aliquot into an electrothermal atomizer. Atomization and measurement of the absorptio
25、n of the resonance line energy from the spectrum of the element being determined. Calibration by the standard additions method: an initial semi-quantitative determination is carried out using a single incremental addition; a second quantitative determination is carried out using two incremental addi
26、tions to the diluted test solution, to obtain the optimum concentration range for sensitivity and linearity. NOTE 1For this determination, it is necessary to use a corrector of non-specific absorption. The procedure using standard additions was selected to enable the method to be applied to ferronic
27、kel samples with widely variable iron and nickel content ratios. It also eliminates the need to find and use very pure iron for matching the test sample matrix in calibrations solutions. 4 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and onl
28、y grade 2 water as specified in ISO 3696. 4.1 High purity metals or compounds, 99,9 % (m/m) minimum, as specified in the relevant part of ISO 11438. 4.2 Nitric acid (HNO3), 20= 1,41 g/ml. The same bottle of acid shall be used for the entire analysis. 4.3 Nitric acid (HNO3), 20= 1,41 g/ml, diluted 1
29、+ 1. Carefully mix together a known volume of the nitric acid (4.2) with the same volume of water. 4.4 Standard solutions Prepare separately for each metal as specified in the relevant part of ISO 11438. 4.4.1 Standard reference solution, 1 000 mg/l of analyte. 4.4.2 Standard solution, 10,0 mg/l of
30、analyte. 4.4.3 Working standard solution, 1,0 mg/l of analyte. 5 Apparatus Glass and plastics bottles used to store all solutions shall be suitably cleaned by soaking for several hours in the dilute nitric acid (4.3) and thoroughly rinsed with water. ISO 11438-1:1993(E) 2 BSI 02-2000 Ordinary labora
31、tory apparatus, and 5.1 Volumetric glassware 5.1.1 One-mark volumetric flasks, of capacities 25 ml, 100 ml and 1 000 ml, in accordance with ISO 1042, class A. 5.1.2 Pipettes, in accordance with ISO 648, class A. 5.1.3 Mechanical micropipettes, of capacities 10 4l to 30 4l. 5.2 Atomic absorption spec
32、trometer, fitted with an electrothermal atomizer. 5.2.1 The spectrometer shall be equipped with a background corrector and a rapid-recording system capable of measuring peak heights and peak areas. 5.2.2 The electrothermal atomizer shall be fitted with a pyrolytic graphite tube. Use of a Lvov platfo
33、rm is recommended. 5.2.3 The spectrometer should be capable of using single-element hollow cathode lamps or electrodeless discharge lamps operated at currents recommended by the manufacturer. 6 Sampling and sample preparation 6.1 Sampling and preparation of the laboratory sample shall be carried out
34、 in accordance with ISO 8050. 6.2 The laboratory sample normally is in the form of millings or drillings and no further mechanical preparation of the sample is usually necessary. 6.3 The laboratory sample shall be cleaned by washing with high purity acetone and dried in air, to eliminate any risk of
35、 contamination with oil or grease. 7 Procedure 7.1 Preparation of the test solution 7.1.1 Weigh, to the nearest 0,001 g, 5,000 g of the laboratory sample and transfer this test portion to a 250 ml beaker. Add 50 ml of the dilute nitric acid (4.3). Cover with a watch glass and heat until effervescenc
36、e ceases. NOTE 2Depending on the ferronickel composition, the dissolution of the test portion may not be total (carbon, silica, etc.). 7.1.2 Heat to boiling and maintain boiling to expel nitrogen oxide vapours, then allow to cool. 7.1.3 Filter in a 100 ml one-mark volumetric flask and wash the filte
37、r thoroughly. Make up to the mark with water and mix carefully. 7.1.4 Proceed as directed in the relevant part of ISO 11438. 7.2 Blank test Carry out blank tests in parallel with the determination, following the same procedure and using the same quantities of all the reagents, but omitting the test
38、portion. NOTE 3Two blank tests should be performed in parallel as a precaution if the first blank, used to plot the standard additions graph, became contaminated. 7.3 Determination by the standard additions method 7.3.1 Atomic absorption measurements 7.3.1.1 The spectral lines for each element to be
39、 used in the analysis are specified in the relevant part of ISO 11438. 7.3.1.2 Condition new graphite tubes as instructed by the manufacturer. 7.3.1.3 Check the zero stability and the absence of spectral interference in the atomization device by running the preset heating programme to heat the graph
40、ite tube until it is white hot. 7.3.1.4 Establish the optimum furnace temperature programme in accordance with the manufacturers instructions. 7.3.1.5 The volume injected into the atomizer shall be 10 4l to 30 4l, depending on the analyte sensitivity. 7.3.2 Semi-quantitative estimation of the analyt
41、e content 7.3.2.1 Add 0 ml and 0,5 ml of the working standard solution (4.4.3) to two 25 ml one-mark volumetric flasks, each containing 10,0 ml of the test solution (7.1). Make up to the mark with water and mix thoroughly to obtain the solutions “zero” and 1, respectively. 7.3.2.2 Atomize a preselec
42、ted volume (10 4l to 30 4l) of each of these two solutions. Record the absorbance measurements A0 and A1 for the solution “zero” and 1, respectively. 7.3.2.3 Calculate the semi-quantitative estimate b of the analyte content in the solution “zero”, as directed in 8.1.1. 7.3.3 Quantitative determinati
43、on of the analyte content 7.3.3.1 Add increments of the analyte working standard solution (4.4.3) to a set of three 25 ml one-mark volumetric flasks, each containing 10,0 ml of the test solution (7.1), to obtain, after making up to the mark with water and mixing, final solutions whose analyte conten
44、ts correspond to concentration Me of the solution “zero” (see 7.3.2.1) in the first flask, to concentration Me+ b in the second, and concentration Me+ 2b in the third. ISO 11438-1:1993(E) BSI 02-20003 7.3.3.2 Add the same increments of the analyte working standard solution (4.4.3) as were used in 7.
45、3.3.1 to another set of three 25 ml one-mark volumetric flasks, each containing 10,0 ml of the blank test solution (7.2). Make up to the mark and mix thoroughly. 7.3.3.3 Atomize the preselected volume (10 4l to 30 4l) of the solutions resulting from the blank test (see 7.3.3.2). Record three absorba
46、nce measurements for each of the solutions. 7.3.3.4 Atomize the preselected volume (10 4l to 30 4l) of the three solutions obtained in 7.3.3.1. Record three absorbance measurements for each of the solutions. 7.3.3.5 Calculate the mean of the three absorbance measurements of each solution, as recorde
47、d in 7.3.3.3 and 7.3.3.4. 7.3.4 Plotting of standard additions 7.3.4.1 For the test solutions obtained in 7.3.3.1, plot the mean absorbance values as a function of the concentrations. The intercept on the x-axis corresponds to the test solution whose analyte content is unknown. Plot the same type of
48、 graph for the blank solutions obtained in 7.3.3.2. NOTE 4This procedure is applicable to the linear part of the graphs. 7.3.4.2 Calculate the concentration Me, in micrograms per litre, of the analyte in the test solution as directed in 8.1.2. 7.4 Number of determinations Carry out the determination
49、 at least in duplicate. 8 Expression of results 8.1 Calculation 8.1.1 Semi-quantitative estimation Plot absorbances A0 and A1 versus concentrations of the solutions “zero” and 1, respectively, to obtain the graph shown in Figure 1. Figure 1 Graph of semi-quantitative standard additions ISO 11438-1:1993(E) 4 BSI 02-2000 Calculate b, the semi-quantitative estimate of the analyte concentration, in micrograms per litre, in the solution “zero”, using equation (1) as follows: Thus 8.1.2 Quantitative determination The standard