1、 ISO 2014 Jewellery Determination of palladium in palladium jewellery alloys ICP-OES method using yttrium as internal standard element Joaillerie, bijouterie Dosage du palladium dans les alliages de palladium pour la joaillerie, bijouterie Mthode par ICP-OES utilisant lyttrium comme talon interne IN
2、TERNATIONAL STANDARD ISO 11495 Second edition 2014-12-15 Reference number ISO 11495:2014(E) ISO 11495:2014(E)ii ISO 2014 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2014 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in a
3、ny form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case post
4、ale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ISO 11495:2014(E)Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Short description of method 1 5 Reagent
5、s 2 6 Equipment . 2 7 Sampling 2 8 Procedure. 2 8.1 Internal standard solution 2 8.2 Calibration solutions 3 8.3 Sample solutions . 3 8.4 Measurements . 3 8.5 Calculation and expression of results 4 9 Repeatability 7 10 Test report . 7 Bibliography 8 ISO 2014 All rights reserved iii ISO 11495:2014(E
6、) 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 out through ISO technical committees. Each member body interested in a subject for which a
7、 technical committee has been 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 matte
8、rs of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This doc
9、ument was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all
10、such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and
11、does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary inf
12、ormation The committee responsible for this document is ISO/TC 174, Jewellery. This second edition cancels and replaces the first edition (ISO 11495:2008), which has been technically revised with the following changes: a) change in the scope that this method is the referee method; b) addition of a w
13、arning in Clause 8 that suitable health and safety procedures should be followed; c) addition of a standard solution in 8.1; d) addition of an alternative calibration solution in 8.2.2; e) addition of an alternative sample solution in 8.3.2; f) addition of an alternative route for calculation in 8.5
14、.4; g) International Standard editorially revised.iv ISO 2014 All rights reserved ISO 11495:2014(E) Introduction The following definitions apply in understanding how to implement an ISO International Standard and other normative ISO deliverables (TS, PAS, IWA): “shall” indicates a requirement; “shou
15、ld” indicates a recommendation; “may” is used to indicate that something is permitted; “can” is used to indicate that something is possible, for example, that an organization or individual is able to do something. ISO/IEC Directives, Part 2 (sixth edition, 2011), 3.3.1 defines a requirement as an “e
16、xpression in the content of a document conveying criteria to be fulfilled if compliance with the document is to be claimed and from which no deviation is permitted.” ISO/IEC Directives, Part 2 (sixth edition, 2011), 3.3.2 defines a recommendation as an “expression in the content of a document convey
17、ing that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required, or that (in the negative form) a certain possibility or course of action is deprecated but not prohi
18、bited.” ISO 2014 All rights reserved v Jewellery Determination of palladium in palladium jewellery alloys ICP-OES method using yttrium as internal standard element 1 Scope This International Standard describes a method for the determination of palladium in palladium jewellery alloys, preferably with
19、in the range of fineness specified in ISO 9202, by means of inductively coupled plasma optical emission spectrometry (ICP-OES). The preferred palladium content of the alloys lies between 500 (parts per thousand) and 950 palladium. NOTE This method can be used to analyse other contents of palladium.
20、This method is intended to be used as the recommended method for the determination of fineness in alloys covered by ISO 9202. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated referenc
21、es, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 11596, Jewellery Sampling of precious metal alloys for and in jewellery and associated products 3 T erms a nd definiti ons For the purposes of this docume
22、nt, the following terms and definitions apply. 3.1 bracketing running of standards and samples in the following sequence: low standard sample high standard sample low standard sample high standard sample low standard sample high standard 4 Short description of method At least two accurately weighed
23、samples are dissolved in aqua regia and made up to an exactly weighed mass. Exactly weighed portions (aliquots) of these sample solutions are mixed with the internal standard and made up to the standard measuring volume. Using ICP-OES, the palladium content of the sample solution is measured by comp
24、arison of the ratio intensities of the spectral emission of palladium (recommended line is 340,45 nm) and yttrium (at 371,03 nm) or other appropriate lines, with the ratios for solutions containing known masses of palladium and yttrium, using the bracketing method. Other palladium emission lines may
25、 be used, but have to be checked for spectral interferences and the instrumental performance. INTERNATIONAL ST ANDARD ISO 11495:2014(E) ISO 2014 All rights reserved 1 ISO 11495:2014(E) 5 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only
26、distilled water or water of equivalent purity. All reagents shall be palladium free. 5.1 Hydrochloric acid (HCl), approximately 30 % to 37 % HCl (mass fraction). 5.2 Nitric acid (HNO 3 ), approximately 65 % to 70 % HNO 3(mass fraction). 5.3 Pure palladium (Pd). The palladium content shall be at leas
27、t 999,9 . If a lower palladium content (999,5 ) is used, appropriate corrections could be applied. 5.4 Internal standard. An yttrium compound like yttrium chloride (YCl 3 6 H 2 O) or yttrium oxide (Y 2 O 3 ) in analytical grade. 5.5 Aqua regia. Mix 3 volumes of hydrochloric acid (5.1) and 1 volume o
28、f nitric acid (5.2). 6 Equipment 6.1 Customary laboratory apparatus. 6.2 ICP-OES, capable of simultaneously measuring the palladium emission line and the emission line of the internal standard yttrium with a minimum optical resolution of 0,02 nm. 6.3 Analytical balance, with a reading accuracy of 0,
29、01 mg. 7 Sampling The sampling procedure shall be performed in accordance with ISO 11596. 8 Procedure WARNING Suitable health and safety procedures should be followed. 8.1 Internal standard solution Dissolve approximately 680 mg YCl 3 6H 2 O (5.4) in 200 ml water and make up to 1 000 ml with water.
30、Alternatively, dissolve approximately 250 mg Y 2 O 3in a mixture of 25 ml water and 25 ml nitric acid and make up to 1 000 ml with water. Due to the sensitivity of the instrument, the concentration may be changed to achieve optimum performance. This also applies to the calibration solutions (see 8.2
31、) and the sample solutions (see 8.3).2 ISO 2014 All rights reserved ISO 11495:2014(E) 8.2 Calibration solutions 8.2.1 Weigh approximately 100 mg of palladium accurately to 0,01 mg into a tared 100 ml volumetric flask and add 40 ml of aqua regia (5.5). Heat gently until complete dissolution of the sa
32、mple. Allow to cool. Make up with water to 100 ml and mix thoroughly. Weigh this palladium stock-solution. Weigh approximately 4,5 g, 5,5 g, 6,5 g, 7,5 g, 8,5 g, 9,5 g, and 9,8 g of the palladium stock solution accurately to at least 0,001 g, each into a 100 ml volumetric flask. Add 10 g of the inte
33、rnal standard solution (8.1) accurate to at least 0,001 g. Add 10 ml HCl (5.1) and make up to 100 ml with water. Mix thoroughly. In the presence of certain other elements (e.g. silver), it can be necessary to increase the HCl concentration to a maximum of 50 ml. The acid concentration of calibration
34、 solutions and sample solutions shall be consistent. 8.2.2 Alternatively weigh 45 mg, 55 mg, 65 mg, 75 mg, 85 mg, 95 mg, and 98 mg palladium accurately to 0,01 mg each into a 1 l flask and dissolve in 100 ml HCl (5.1) plus 30 ml HNO3 (5.2). Add 100 g accurately to 0,01 g of the internal standard sol
35、ution (8.1). Add 100 ml HCl (5.2) and make up to 1 l with water. Mix thoroughly. In the presence of certain other elements (e.g. silver), it can be necessary to increase the HCl concentration to a maximum of 500 ml. The acid concentration of calibration solutions and sample solutions shall be consis
36、tent. NOTE Depending on the range of the palladium contents in the samples, not all the standards are necessary. 8.3 Sample solutions 8.3.1 Weigh approximately 100 mg of the sample to the nearest 0,01 mg, dissolve and treat the sample as described in 8.2.1. Weigh approximately 10 g of this sample st
37、ock solution accurately to 0,001 g into a 100 ml volumetric flask and add 10 g of the internal standard solution (8.1) accurately to 0,001 g. Add 10 ml HCl (5.1) and make up to 100 ml. Mix thoroughly. In the presence of certain other elements (e.g. silver), it can be necessary to increase the HCl co
38、ncentration to a maximum of 50 ml. The acid concentration of calibration solutions and sample solutions shall be consistent. 8.3.2 Alternatively weigh 100 mg sample accurately to 0,01 mg into a 1 l flask and dissolve and treat the sample as described in 8.2.2. In the presence of certain other elemen
39、ts (e.g. silver), it can be necessary to increase the HCl concentration to a maximum of 500 ml. The acid concentration of calibration solutions and sample solutions shall be consistent. NOTE Attention is drawn to the possibility that smaller samples will also be more affected by any variation on hom
40、ogeneity in the material sampled. 8.4 Measurements The data processing unit of the ICP-OES is used to establish a measuring program in which the intensities of the emission lines of Pd 340,45 nm and of the internal standard element yttrium (at 371,03 nm) can be measured simultaneously. Set up the in
41、strument in accordance with the manufacturers instructions and choose appropriate background correction positions. A clean torch, spray chamber, and sample uptake tubes shall be used and the plasma shall be stabilized before use, following the recommendations of the instruments manufacturer. Each st
42、andard and sample solution shall have a minimum stabilization time of 30 s, followed by the integration times and the number of integrations required to obtain a maximum relative standard ISO 2014 All rights reserved 3 ISO 11495:2014(E) deviation (RSD) of 0,2 % see 8.5.2, Formula (1). The accurate m
43、ass of palladium of the sample solution is derived from the measurement of the two calibration solutions bracketing the rough value of the sample solution see 8.5.3, Formula (4) or 8.5.4, Formula (9), depending on the way of calibration and sample solution preparation. 8.5 Calculation and expression
44、 of results 8.5.1 If the solution has been prepared in accordance with 8.2.1 and 8.3.1, use 8.5.3 for calculation or if the solution is prepared according to the alternative route (8.2.2 and 8.3.2), use 8.5.4 for calculation. 8.5.2 The method of internal standardization is based on the linear relati
45、on between the intensity ratios I Pd /I Yand the concentration ratios C Pd /C Yor, better, mass ratios m Pd /m Y . Using the same mass of yttrium (internal standard solution) to prepare all solutions, it is not necessary to have an exact volume of the measuring solutions. The accuracy of the 100 ml
46、volumetric flask is satisfactory. The other important advantage of always referring to the same mass of the internal standard is that all calculations can be done with m Pdinstead of m Pd /m Y , nominal. In general, the data processing unit provides the quotients from the simultaneously registered s
47、ingle measurements of the palladium and the yttrium intensities. If the mean value, Q , of the five intensity quotients (Q 1 , Q 2 , Q 3 , Q 4 , Q 5 ) belonging to each solution is calculated using Formula (1): (1) then this mean value shall have an RSD from Q not larger than 0,2 %. 8.5.3 In view of
48、 deviations from the nominal mass, m IS , in grams, of the internal standard solution (m IS= 10,000 g), each intensity quotient belonging to a measuring solution shall be corrected by the corresponding real mass of internal standard solution W IS,n , in grams, used to prepare this measuring solution
49、. The corrected quotient, Q C , is calculated using Formula (2): (2) To determine the palladium content of the sample using the corrected intensity quotient, the exact masses of palladium in the calibration solutions m Pd,Cs,n , in milligrams, are required. These masses shall be calculated individually for each calibration solution or calibration point using Formula (3): (3) where W Pd, SS is the mass
