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1、INTERNATIONAL STANDARD IS0 7530-I First edition 1990-12-15 Corrected and reprinted 1992-02-15 Nickel alloys - Flame atomic absorption spectrometric analysis - Part I: General requirements and sample dissolution Alliages de nickel - Analyse par spectromPtrie d absorption atomique dans la flamme - Par
2、tie 1: CaractCristiques gbn6rales et mise en solution de I Cchantillon Reference number is0 7530-I :I 990( E) IS0 7530-1:1990(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing Interna
3、tional Standards is normally carried out through IS0 technical committees. 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, govern- mental and non-governmental, in liaison wit
4、h ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an
5、 Inter- national Standard requires approval by at least 75% of the member bodies casting a vote. International Standard IS0 7530-I was prepared by Technical Committee ISO/TC 155, Nickel and nickel alloys, Sub-Committee SC 4, Analysis of nickel alloys. IS0 7530 consists of the following parts, under
6、the general title Nickel alloys - Flame atomic absorption spectrometric analysis: - Part 1: General requirements and sample dissolution - Part 2: Determination of cobalt content - Part 3: Determination of chromium content - Part 4: Determination of copper content - Part 5: Determination of iron cont
7、ent - Part 6: Determination of manganese content - Part 7: Determination of aluminium content - Part 8: Determination of silicon content - Part 9: Determination of vanadium content Annex A forms an integral part of this part of IS0 7530. Annex B is for information only. 0 IS0 1990 All rights reserve
8、d. No part of this publication may be reproduced or utilized In any form or by any means, electronic or mechanical, Including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case Postale 56 l CH-1211 Gerkve 20 l Switzerland
9、 Printed In Switzerland ii IS0 7530-1:1990(E) Introduction This part of IS0 7530 is to be used in conjunction with the other parts which specify methods for the determination of individual elements in nickel alloys by flame atomic absorption spectrometry. Although the analytical methods are specifie
10、d in independent Inter- national Standards, it is possible to determine more than one element on a single test solution by adjustment of the sample weight and initial and subsequent dilutions. . . . III INTERNATIONAL STANDARD IS0 7530-1:1990(E) Nickel alloys - Flame atomic absorption spectrometric a
11、nalysis - Part 1: General requirements and sample dissolution WARNING - The manufacturer s recommendations should be closely followed and particular attention ,_ is drawn to the following safety points: a) the explosive nature of acetylene, and regulations concerning its use, b) the need to shield t
12、he eyes of the operator from ultraviolet radiation by means of tinted glass, c) the need to keep the burner head clear of deposits because a badly clogged burner may cause a flashback, d) the need to ensure that the liquid trap is filled with water, e) always spray distilled water between the test s
13、olutions, blank solution and/or calibration solutions. 1 Scope 1.1 IS0 7530 specifies flame atomic absorption methods for the determination of up to 4 % (m/m) of cobalt, chromium, copper, iron, manganese and aluminium, up to 2 % (nt/m) of silicon and from 0,05 % (m/m) to 1 % (nz/m) of vanadium in ni
14、ckel alloys. Other elements may be added in subsequent parts of IS0 7530. Typical compositions of some nickel alloys are given in annex B. 1.2 This part of IS0 7530 specifies the general re- quirements for analysis by flame atomic absorption, preparation and dissolution of the test sample, method of
15、 calculation and the procedures used for the evaluation of the repeatability and reproduc- ibility of the individual methods specified in the other parts of IS0 7530. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of thi
16、s part of IS0 7530. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of IS0 7530 are encouraged to investi- gate the possibility of applying the most recent edi- tions of the standards indicated below.
17、Members of IEC and IS0 maintain registers of currently valid International Standards. 1 -,-,- IS0 7530-1:1990(E) IS0 385-1:1984, Laboratory glassware - Burettes - Part 1: General requirements. IS0 648:1977, Laboratory glassware - One-mark pipettes. IS0 1042:1983, Laboratory glassware - One-mark volu
18、metric flasks. IS0 5725:1986, Precision of test methods - Defermi- nation of repeatability and reproducibility for a stan- dard test method by inter-laboratory tests. 3 Principle Dissolution of a test portion in acid, evaporation of excess acid and redissolution of the salts. Addition of an ionizati
19、on suppressant, if necessary, and dilution of the solution to a known volume. Aspiration of the test solution, after a secondary di- lution, if necessary, into the air-acetylene or nitrous oxide-acetylene flame of an atomic absorption spectrometer. Measurement of the absorption of the resonance line
20、 energy from the spectrum of the element being determined and comparison with that of calibration solutions of the same element. 4 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 High
21、purity metals, 99,9 % (m/m) minimum, as specified in the relevant pat-l of IS0 7530. 4.2 Nitric acid, (HNO,), 20 = I,41 g/ml 4.3 Nitric acid, (HNO,), 20 = I,41 g/ml diluted (1 + 1). 4.4 Hydrochloric acid, (HCI), 20 = I,18 g/ml. 4.5 Hydrochloric acid, (HCI), p20 = I,18 g/ml di- luted (1 + 1). 4.6 Nit
22、ric acid-hydrochloric acid mixture. CAUTION - This acid mixture is highly corrosive and unstable. Noxious gas (chlorine) is liberated on standing. It shall be prepared and used in a fume cupboard and shall not be kept in a closed container. Carefully mix 1 part of nitric acid (4.2) and 3 parts of hy
23、drochloric acid (4.4). This mixture is not stable and should be prepared only as needed. 2 4.7 Standard reference solutions, 1,000 g/l of metal. Prepare separately for each metal as specified in the appropriate part of IS0 7530. 5 Apparatus Ordinary laboratory apparatus, and 5.1 Atomic absorption sp
24、ectrometer 5.1.1 The atomic absorption spectrometer used in this method shall meet the instrument performance parameters given in annex A. 5.1.2 The instrument shall be equipped with burner heads suitable for both an air-acetylene and a nitrous oxide-acetylene flame. 5.1.3 The instrument should be c
25、apable of using single element hollow cathode or electrodeless dis- charge lamps operated at currents recommended by the manufacturer. 5.2 Volumetric glassware 5.2.1 Burettes, of capacity 50 ml, graduated in div- isions of 0,l ml in accordance with IS0 385-1, class A. 5.2.2 Pipettes, in accordance w
26、ith IS0 648, class A. 5.2.3 Volumetric flasks, in accordance with IS0 1042, class A. 6 Sampling and sample preparation 6.1 Sampling and preparation of the laboratory sample shall be carried out by normal agreed pro- cedures or, in case of dispute, by the relevant Inter- national Standard. 6.2 The la
27、boratory sample normally is in the form of millings or drillings and no further preparation of the sample is necessary. 6.3 If it is suspected that the laboratory sample is contaminated with oil or grease from the milling or drilling process, it shall be cleaned by washing with high purity acetone a
28、nd drying in air. 6.4 If the laboratory sample contains particles or pieces of widely varying sizes, the test sample should be obtained by riffling. -,-,- IS0 7530-l :I 990(E) 7 Procedure 7.1 Preparation of test solution - General method 7.1.1 Weigh, to the nearest 0,001 g, I,00 g of the laboratory
29、sample and transfer to a clean unetched 600 ml beaker. Add 20 ml of the nitric acid- hydrochloric acid mixture (4.6). Apply sufficient heat to initiate and maintain the reaction until dissolution is complete. If the alloy resists dissolution, some adjustment of the acid mixture may be required. Add
30、hydrochloric acid (4.4) in 1 ml increments and con- tinue heating to dissolve the sample. 7.1.2 Using a low heat, evaporate the solution just to dryness. Do not bake. Cool to about 50 C, add 25 ml of hydrochloric acid (4.4) and again evaporate just to dryness. Add a further 25 ml of hydrochloric aci
31、d and repeat the evaporation. 7.1.3 Cool to about 50 C, add 5 ml of hydrochloric acid (4.4) and 20 ml of water and heat to dissolve the salts. 7.1.4 Proceed as directed in the relevant part of IS0 7530. NOTES 1 Some alloys having a high copper content may be dissolved in nitric acid diluted 1 + 1. F
32、or some alloys an acid mixture containing 30 ml hydrochloric acid and 2 ml of nitric acid is more effective. 2 The general method of dissolution may be modified as specified in other parts of IS0 7530. 3 If sample inhomogeneity is suspected, a larger mass of sample (10 g to 50 g) may be taken for an
33、alysis. How- ever, an aliquot portion corresponding to a 1 g sample shall be taken from such a solution and processed in ac- cordance with the procedure given. 7.2 Blank test Carry out a blank test in parallel with the determi- nation, following the same procedure and using the same quantities of al
34、l the reagents. 7.3 Preparation of calibration solutions 7.4.1.2 Set the required instrument parameters ac- cording to the manufacturer s recommendations. Light the burner and aspirate water until thermal equilibrium is reached. The flame conditions will vary according to the element being determine
35、d. Zero the instrument. 7.4.1.3 Ensure that the instrument meets the per- formance requirements given in annex A. Optimum settings for the operating parameters vary from in- strument to instrument. Scale expansion may have to be used to obtain the required readability. 7.4.1.4 Ensure that the calibr
36、ation solutions and the test solution(s) are within 1 OC of the same tem- perature. 7.4.1.5 Aspirate water and zero the instrument. 7.4.1.6 Aspirate the calibration solutions and the test solution(s) and note the reading to determine the approximate concentration of the test solutions. 7.4.1.7 Aspir
37、ate water until the initial reading is obtained. Zero the instrument if necessary. 7.4.1.8 Aspirate the calibration solutions and the test solution(s) in the order of increasing instrument response, starting with the zero member solution. When a stable response is obtained, record the reading. Flush
38、 the system by aspirating water be- tween each test or calibration solution. 7.4.1.9 Repeat the measurement of the full set of the calibration and test solutions twice more and record the data. 7.4.2 Preparation of calibration graphs Plot the average instrument reading against the concentration of t
39、he analyte in the calibration sol- utions for each set of measurements. Proceed with the calculations as directed in clause 8. NOTE 4 Some instruments may be adjusted to give a read-out directly in concentration of the analyte. A graph of instrument response versus concentration should be plotted to
40、 check the validity of the readings. 7.5 Number of determinations Carry out the determination at least in duplicate. Proceed as directed in the relevant part of IS0 7530. 8 Expression of results 7.4 Calibration and determination 8.1 Calculation 7.4.1 Atomic absorption measurements 7.4.1.1 The spectr
41、al lines for each element to be used in the analysis are specified in the relevant part of IS0 7530. 8.1.1 Determine the concentration of the analyte in the test solution from the corresponding calibration graphs for each of the three sets of instrument readings recorded. 3 IS0 7530-l :I 990(E) 8.1.
42、2 Calculate the percentage by mass of the analyte in the test sample using the formula pxVxF m x 1o-4 where P is the analyte concentration, in milli- grams per litre, found in the test solution less the blank; V is the volume, in millilitres, of the initial test solution: F is the dilution factor fo
43、r the secondary dilution; m is the mass, in grams, of the test portion. NOTE 5 The average of the results from the three readings as calculated comprises a single determination. The three results give an indication of the precision of the atomic absorption measurements. 8.2 Precision 8.2.1 Laborator
44、y tests The methods in the subsequent parts of IS0 7530 have been subjected to interlaboratory testing. Samples were analysed in duplicate on different days. 8.2.2 Statistical analysis 8.2.2.1 Results from the interlaboratory test pro- gramme were evaluated according to IS0 5725. The data were teste
45、d for statistical outliers by the Cochran and Dixon tests given in IS0 5725. 8.2.2.2 The principle of the Cochran test is that a set of results is an outlier if the within-laboratory variance is too large in relation to others. Dixon s test is to determine if the mean from a laboratory is too far fr
46、om the other laboratory means. Both tests were applied at the 95 % confidence level. 8.2.2.3 Repeatability and reproducibility were cal- culated according to IS0 5725 at the 95 % confi- dence level. Results of the statistical analysis, including the within-laboratory and between- laboratory standard
47、 deviations are given for each element in the relevant part of this IS0 7530. 9 Test report The test report shall include the following infor- mation: a) the reference to the method used; b) the results of the analysis; c) the number of independent replications; d) any unusual features noted during
48、the analysis; e) any operation not included in this part of IS0 7530 or regarded as optional. -,-,- IS0 7530-1:1990(E) Annex A (normative) Checking of spectrometer performance parameters A.1 Introduction The performance of atomic absorption spec- trometers of the same or different manufacture may va
49、ry from instrument to instrument. It is therefore essential to establish that a particular instrument meets certain performance requirements before it is used in the methods specified in IS0 7530. A.2 Initial instrument adjustments A.2.1 Set up the atomic absorption spectrometer to operate with an air-acetylene or nitrous oxide- acetylene flame using a single slot laminar flow burner head according to the manufacturer s in- structions. A.2.2 Use a single element hollo