1、BSI Standards PublicationBS ISO 15096:2014Jewellery Determination of silver in 999 0/00silver jewellery alloys Difference method using ICP-OESBS ISO 15096:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 15096:2014. It supersedes BS ISO 15096:2008 which is
2、withdrawn.The UK participation in its preparation was entrusted to Technical Committee STI/53, Specifications and test methods for jewellery and horology.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all
3、 the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2014.Published by BSI Standards Limited 2014ISBN 978 0 580 74807 3ICS 39.060Compliance with a British Standard cannot confer immunity from legal obligations.This British Stan
4、dard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2014.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 15096:2014 ISO 2014Jewellery Determination of silver in 999 0/00silver jewellery alloys Difference method using I
5、CP-OESJoaillerie, bijouterie Dosage de largent dans de largent 999 0/00 Mthode de la differnce utilisant ICP OESINTERNATIONAL STANDARDISO15096Second edition2014-12-15Reference numberISO 15096:2014(E)BS ISO 15096:2014ISO 15096:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 201
6、4All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any 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 requeste
7、d from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 15096:2014ISO 15096:2014(E)Contents PageFore
8、word ivIntroduction v1 Scope . 12 Normative references 13 Principle 14 Sampling 15 Reagents 16 Apparatus . 27 Procedure. 27.1 Sample solution 27.2 Silver matrix calibration solutions (10 g/l) . 27.3 Aqua regia matrix calibration solutions 37.4 Measurements . 38 Calculation and expression of results
9、. 38.1 Calibration curves 38.2 Calculation 38.3 Repeatability . 49 Test report . 4Annex A (normative) Wavelengths . 5Bibliography 6 ISO 2014 All rights reserved iiiBS ISO 15096:2014ISO 15096:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national
10、 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 been established has the right to be represented on that committee. Internationa
11、l 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 standardization.The procedures used to develop this document and those intended fo
12、r 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 document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.or
13、g/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 such patent rights. Details of any patent rights identified during the development of the document will be
14、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 does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions r
15、elated 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 information.The committee responsible for this document is ISO/TC 174, Jewellery.This second edition cancels an
16、d replaces the first edition (ISO 15096:2008), which has been technically revised with the following changes:a) change in the scope that this method is the referee method;b) addition of silver and silver nitrate in Clause 5;c) addition of a warning in Clause 7 that suitable health and safety procedu
17、res should be followed;d) change of sample solution in 7.1;e) split of 7.2 “Calibration solution” into 7.2 “Silver matrix calibration solutions” and 7.3 “Aqua regia matrix calibration solutions”;f) change of 8.2 “Method of calculation”;g) change of repeatability to 0,1 ;h) amendment of wavelengths i
18、n Table A.1;i) standard editorially revised.iv ISO 2014 All rights reservedBS ISO 15096:2014ISO 15096:2014(E)IntroductionThe following definitions apply in understanding how to implement an ISO International Standard and other normative ISO deliverables (TS, PAS, IWA). “shall” indicates a requiremen
19、t; “should” 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 a
20、s an “expression 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
21、conveying 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 n
22、ot prohibited.” ISO 2014 All rights reserved vBS ISO 15096:2014BS ISO 15096:2014Jewellery Determination of silver in 999 0/00silver jewellery alloys Difference method using ICP-OES1 ScopeThis International Standard specifies the analytical procedure for the determination of silver with a nominal con
23、tent of at least 999 (parts per thousand) by measuring specific elements listed in Table A.1.This International Standard specifies a method intended to be used as the recommended method for the determination of fineness in 999 silver alloys covered by ISO 9202.2 Normative referencesThe following doc
24、uments, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 11596, Jewellery Samp
25、ling of precious metal alloys for and in jewellery and associated products3 PrincipleThe sample is weighed and dissolved in nitric acid to prepare a 10 g/l solution. The suspension, which can be present in that solution, is isolated by centrifugation and dissolved in aqua regia. Both solutions are a
26、nalysed separately by ICP-OES and the total content of each impurity in the sample is obtained by adding together the results of the two analyses. The silver content is obtained by subtraction of the total content of impurities in the sample from 1 000 .4 SamplingThe sampling procedure shall be perf
27、ormed in accordance with ISO 11596.5 ReagentsDuring the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity.5.1 Hydrochloric acid (HCl), approximately 30 % to 37 % HCl (mass fraction).5.2 Nitric acid (HNO3), appro
28、ximately 65 % to 70 % HNO3(mass fraction).5.3 Stock solution 1 (shall not contain any chloride), all elements given in Table A.1 (100 mg/l each) in 1 mol/l HNO3(5.2). The solution should be prepared just before use.5.4 Stock solution 2 (may contain both chlorides and nitrates), Al, Au, Cr, Fe, Mg, N
29、i, Pt, and Sn (100 mg/l each) in 1 mol/l HCl (5.2) or HNO3(5.3). The solution should be prepared just before use.5.5 Aqua regia (should be prepared just before use).Mix three volumes of hydrochloric acid (5.2) and one volume of nitric acid (5.3).INTERNATIONAL STANDARD ISO 15096:2014(E) ISO 2014 All
30、rights reserved 1BS ISO 15096:2014ISO 15096:2014(E)5.6 Silver, of 999,9 minimum or;5.7 Silver nitrate, of photographic quality.6 Apparatus6.1 Customary laboratory apparatus.6.2 ICP OES, with fixed and/or scanning channels, optical resolution of 0,02 nm for the relevant elements and a detection limit
31、 of 0,05 mg/l or better, and capability of background correction.NOTE For preferably used wavelength, see Annex A.6.3 Analytical balance, with a reading accuracy of 0,1 mg.6.4 Centrifuge, suitable for 10 ml to 50 ml tubes and rotating at 3 000 r/min (revolution per minute) or more.7 ProcedureWARNING
32、 Suitable health and safety procedures should be followed.7.1 Sample solutionEach sample has to be analysed twice and shall be prepared as follows.Weigh approximately 500 mg of the sample portion to the nearest 0,1 mg, transfer into a 50 ml beaker, and add 7,5 ml of H2O and 7,5 ml of HNO3(5.2). Heat
33、 gently until complete dissolution of the sample and continue to heat to expel the nitrogen oxides. Add 10 ml of water. After cooling to room temperature, transfer the solution from the 50 ml beaker to the centrifuge tube. Centrifuge the mixture at 3 000 r/min for 5 min and transfer the liquid phase
34、 into a 50 ml volumetric flask. Add 5 ml of water to the residue, centrifuge the mixture again at 3 000 r/min for 5 more minutes, and add the newly formed liquid phase to the 50 ml volumetric flask. This operation is repeated for three times. Make up the volume of the solution with water to 50 ml. A
35、nalyse this solution without delay using the calibration solutions specified in 7.2.Add 2 ml of freshly prepared aqua regia (5.5) to the residue after centrifugation. Heat at 80 C for 2 h. Cool to room temperature, transfer to a 5 ml volumetric flask, rinse with water, and make up with water to 5 ml
36、. Analyse this solution using the aqua regia calibration solutions specified in 7.3.7.2 Silver matrix calibration solutions (10 g/l)Blank solution 1. Weigh approximately 500 mg of silver (5.6) or approximately 787 mg of silver nitrate (5.7) and dissolve as specified in 7.1. Allow to cool and make up
37、 to 50 ml with water and mix thoroughly.Calibration solution 1. Weigh approximately 500 mg of silver (5.6) or approximately 787 mg of silver nitrate (5.7) and dissolve as specified in 7.1. Allow to cool and add 2,5 ml of the stock solution 1 (5.3) and make up the solution up to 50 ml with water and
38、mix thoroughly. This solution is unstable and should be prepared just before use.2 ISO 2014 All rights reservedBS ISO 15096:2014ISO 15096:2014(E)7.3 Aqua regia matrix calibration solutionsBlank solution 2. Transfer 20 ml of aqua regia (5.5) into a 50 ml volumetric flask. Make up to 50 ml with water
39、and mix thoroughly.Calibration solution 2. Transfer 20 ml of aqua regia (5.5) into a 50 ml volumetric flask, add 2,5 ml of the stock solution 2 (5.4), make up to 50 ml with water, and mix thoroughly.7.4 MeasurementsSet up the instrument in accordance with the manufacturers instructions and choose ap
40、propriate background correction positions. A clean torch, spray chamber, and sample uptake tubes shall be used and the plasma shall be stabilized also before use, following the recommendations of the instruments manufacturer.Spray the calibration solutions 1 and 2 in accordance with the defined inst
41、rument calibration procedure and then run the analytical procedure for the sample solutions. The result shall be displayed with enough decimal places to provide an accurate indication of concentrations at the detection limits of the relevant elements.Each solution shall have a stabilization time of
42、at least 30 s followed by five integrations of at least 5 s each for the determination of the net intensities (i.e. background-corrected).The rinsing time between each measurement shall be sufficient to allow the signal of each impurity to come back to the baseline.Each analysis (silver 10 g/l and a
43、qua regia) has to be carried out separately with the calibration solutions specified in 7.2 and 7.3.8 Calculation and expression of results8.1 Calibration curvesCalculate the calibration curves for each element using the blank solutions and the calibration solutions.8.2 CalculationBy means of the ca
44、libration curves (see 8.2), convert the net intensity values into concentration values for both analyses in silver 10 g/l matrix and aqua regia matrix using Formula (1) to calculate the mass ratio of each relevant element (Wi).WcVmcVmi=+i,Ag s,Agsi,ar s,ars(1)whereci,Agis the concentration of elemen
45、t i in the silver (10 g/l) matrix sample solution, in mg/l;Vs,Agis the volume of the silver (10 g/l) matrix sample solution, in litres (0,05 l as defined in 7.1);ci,aris the concentration of element i in the aqua regia matrix sample solution, in mg/l;Vs,aris the volume of the aqua regia matrix sampl
46、e solution, in litres (0,005 l as defined in 7.1);msis the mass of the metallic sample, in milligrams.The detection limit is defined as three standard deviations of the concentration of each individual element measured in the blank solution for the corresponding matrix. ISO 2014 All rights reserved
47、3BS ISO 15096:2014ISO 15096:2014(E)The silver fineness (Wsp), expressed in parts per thousand (), is thus calculated using Formula (2):Wwsp i= ()1000 1000 (2)wherewiis the sum of the mass portion of each element found above its detection limit.8.3 RepeatabilityThe results of duplicate determinations
48、 shall not deviate more than 0,1 of the precious metal fineness. If the variation is greater than this, the assay shall be repeated.9 Test reportThe test report shall include at least the following information:a) identification of the sample including source, date of receipt, form of sample;b) sampl
49、ing procedure;c) the method used by reference to this International Standard, i.e. ISO 11490;d) precious metals content of the sample, in parts per thousand () by mass, as single values and mean values, with the result reported with four significant figures;e) if relevant, any deviations from the method specified in this International Standard;f) any unusual features observed during the determination;g) date of test;h) identification of the laboratory carrying out this analysis;i) signature of the laboratory mana
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