DIN EN ISO 11427-2016 Jewellery - Determination of silver in silver jewellery alloys - Volumetric (potentiometric) method using potassium bromide (ISO 11427 2014) German version EN.pdf

1、December 2016 English price group 8No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 39.060!%y“2599186www.din.deDIN E

2、N ISO 11427Jewellery Determination of silver in silver jewellery alloys Volumetric (potentiometric) method using potassium bromide (ISO 11427:2014);English version EN ISO 11427:2016,English translation of DIN EN ISO 11427:2016-12Schmuck Bestimmung von Silber in Silberschmucklegierungen Volumetrische

3、s (potentiometrisches) Verfahren unter Verwendung von Kaliumbromid (ISO 11427:2014);Englische Fassung EN ISO 11427:2016,Englische bersetzung von DIN EN ISO 11427:2016-12Joaillerie, bijouterie Dosage de largent dans les alliages dargent pour la bijouteriejoaillerie Mthode volumtrique (potentiomtrique

4、) utilisant le bromure de potassium (ISO 11427:2014);Version anglaise EN ISO 11427:2016,Traduction anglaise de DIN EN ISO 11427:2016-12SupersedesDIN EN 31427:199504www.beuth.deDocument comprises 12 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be consid

5、ered authoritative.01.17 DIN EN ISO 11427:2016-12 2 A comma is used as the decimal marker. National foreword The text of ISO 11427:2014 has been prepared by Technical Committee ISO/TC 174 “Jewellery” (Secretariat: DIN, Germany) and has been taken over as EN ISO 11427:2016 according to the decision C

6、EN/BT C137/2015. The responsible German body involved in its preparation was DIN-Normenausschuss Feinmechanik und Optik (DIN Standards Committee Optics and Precision Mechanics), Working Committee NA 027-04-04 AA Analysenmethoden. The DIN Standard corresponding to the International Standard referred

7、to in this document is as follows: ISO 9202 DIN EN ISO 9202 Amendments This standard differs from DIN EN 31427:1995-04 as follows: a) the requirement for sampling has been changed in Clause 6; b) a warning has been added in Clause 7 that suitable health and safety procedures should be followed; c) i

8、n Subclause 7.1.1, the possibility to use watch glasses to cover the beaker has been added; d) in Subclause 7.1.1, the specified volume of water has been deleted; e) it has been clarified in Subclause 7.1.3 that a potassium bromide standard solution is to be used; f) in Subclause 8.1, potassium chlo

9、ride has been changed to potassium bromide; g) the standard has been editorially revised. Previous editions DIN EN 31427: 1994-09, 1995-04 National Annex NA (informative) Bibliography DIN EN ISO 9202, Jewellery Fineness of precious metal alloys EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS

10、O 11427 October 2016 ICS 39.060 Supersedes EN 31427:1994English Version Jewellery - Determination of silver in silver jewellery alloys - Volumetric (potentiometric) method using potassium bromide (ISO 11427:2014) Joaillerie, bijouterie - Dosage de largent dans les alliages dargent pour la bijouterie

11、-joaillerie - Mthode volumtrique (potentiomtrique) utilisant le bromure de potassium (ISO 11427:2014) Schmuck - Bestimmung von Silber in Silberschmucklegierungen - Volumetrisches (potentiometrisches) Verfahren unter Verwendung von Kaliumbromid (ISO 11427:2014) This European Standard was approved by

12、CEN on 26 August 2016. 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 concerning such national standar

13、ds may be obtained on application to the CEN-CENELEC Management Centre 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 language and noti

14、fied to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Ic

15、eland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Mana

16、gement Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 11427:2016 EContents PageEuropean foreword .3Introduction 51 Scope . 62 Normative references 63 Principle 64 Reagents 65 Appa

17、ratus . 76 Sampling 77 Procedure. 77.1 Determination of potassium bromide factor 77.2 Determination . 88 Calculation and expression of results . 88.1 Calculation 88.2 Repeatability . 89 Test report . 9Bibliography . 10DIN EN ISO 11427:2016-12EN ISO 11427:2016 (E)2Foreword 4European foreword The text

18、 of ISO 11427:2014 has been prepared by Technical Committee ISO/TC 174 “Jewellery” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 11427:2016. This European Standard shall be given the status of a national standard, either by publication of an identical

19、text or by endorsement, at the latest by April 2017, and conflicting national standards shall be withdrawn at the latest by April 2017. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsib

20、le for identifying any or all such patent rights. This document supersedes EN 31427:1994. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Cze

21、ch Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdo

22、m. Endorsement notice The text of ISO 11427:2014 has been approved by CEN as EN ISO 11427:2016 without any modification. DIN EN ISO 11427:2016-12EN ISO 11427:2016 (E)3 ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member

23、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. International organizations, governmental

24、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 for its further maintenance are

25、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.org/directives). Attention is dr

26、awn 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 in the Introduction and/or on

27、 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 related to conformity assessm

28、ent, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 174, Jewellery.This second edition cancels and replaces the first edition (

29、ISO 11427:1993) which has been technically revised with the following changes:a) change of requirement for sampling in Clause 6;b) addition of a warning in Clause 7 that suitable health and safety procedures should be followed;c) addition of the possibility to use watch glasses in 7.1.1 to cover the

30、 beaker;d) deletion of the specified volume of water in 7.1.1;e) addition in 7.1.3 that a potassium bromide standard solution is used;f) change in 8.1 from potassium chloride to potassium bromide;g) standard editorially revised.DIN EN ISO 11427:2016-12EN ISO 11427:2016 (E)4 IntroductionThe following

31、 definitions apply in understanding how to implement an ISO International Standard and other normative ISO deliverables (TS, PAS, IWA). “shall” indicates a requirement “should” indicates a recommendation “may” is used to indicate that something is permitted “can” is used to indicate that something i

32、s possible, for example, that an organization or individual is able to do something3.3.1 of the ISO/IEC Directives, Part 2 (sixth edition, 2011) defines a requirement as an “expression in the content of a document conveying criteria to be fulfilled if compliance with the document is to be claimed an

33、d from which no deviation is permitted.”3.3.2 of the ISO/IEC Directives, Part 2 (sixth edition, 2011) defines a recommendation as an “expression in the content of a document conveying that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others

34、, 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 prohibited.”DIN EN ISO 11427:2016-12EN ISO 11427:2016 (E)5 1 ScopeThis International Standard method describes a volumetric m

35、ethod for the determination of silver in jewellery alloys, preferably within the range of fineness stated in ISO 9202.These alloys may contain copper, zinc, cadmium, and palladium. Apart from palladium, which must be precipitated before commencing titration, these elements do not interfere with this

36、 method of determination.This method is intended to be used as the referee method for the determination of fineness in alloys covered by ISO 9202.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application.

37、 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 Sampling of precious metal alloys for and in jewellery and associated products3 PrincipleThe sample is dissolved in dil

38、ute nitric acid. The silver content of the resulting solution is determined by titration with standard potassium bromide solution using a potentiometric indication of the equivalence point.4 ReagentsDuring the analysis, unless otherwise stated, use only reagents of recognized analytical grade and on

39、ly distilled water or water of equivalent purity.4.1 Nitric acid; 33 % HNO3(mass fraction), with sufficiently low content of halides (check with silver nitrate test).4.2 Potassium bromide, solution, c (KBr) = 0,1 mol/l.Dissolve 11,901 g of potassium bromide (dried at 105 C) in water and dilute to 1

40、000 ml.4.3 Disodium dimethylglyoxime octahydrate solution.Dissolve 10 g of disodium dimethylglyoxime octahydrate in 1 000 ml of water.4.4 Pure silver, minimum purity 999,9 parts by mass per thousand ().DIN EN ISO 11427:2016-12EN ISO 11427:2016 (E)6 5 Apparatus5.1 Customary laboratory apparatus.5.2 M

41、otor-driven plunger or piston-type burette, linked to a potentiometer or automatic titrator and capable of delivering increments of 0,05 ml at the equivalence point.5.3 Titration apparatus, with combination silver electrode coated with silver bromide and Hg/Hg2SO4or other suitable reference electrod

42、e.5.4 Analytical balance, with a reading accuracy of 0,01 mg.6 SamplingThe sampling procedure for silver and silver alloys shall be performed in accordance with ISO 11596.7 ProcedureWARNING Suitable health and safety procedures should be followed.7.1 Determination of potassium bromide factor7.1.1 Pr

43、eparation of silver standardsWeigh three samples of silver (4.4); each of 300 mg to 500 mg, accurately to the nearest 0,01 mg, and transfer them into three glass beakers. Add 5 ml of nitric acid (4.1) to each beaker, and warm gently to dissolve the silver. Tops of the beakers can be covered with wat

44、ch glasses. Heat until evolution of nitrogen oxides ceases. Allow to cool. Rinse the watch glasses into beakers. Add the minimum volume of water required to satisfy the requirements of the titration apparatus (5.3) in respect of measurement and stirring. Put the beaker in the titration apparatus (5.

45、3).The mass of the standard silver samples should lie within 20 mg of the mass of silver in the sample portion (8.1).7.1.2 Titration of the standard silver solutionAdd, via the plunger-burette (5.2) under continuous stirring, sufficient potassium bromide solution (4.2) to precipitate about 95 % of t

46、he silver in the solution. Titrate the remaining silver in such a manner that the equivalence point can be interpolated from 0,05 ml additions of the potassium bromide solution.NOTE This split titration approach can be effected automatically, using an automatic titrator with so-called dynamic volume

47、 dosing based on the measured potential difference across the electrodes in the titration apparatus (5.3).7.1.3 Calculation of the potassium bromide standard solution factorThe potassium bromide standard solution factor, F, is calculated using Formula (1):FmV=AgFAgF(1)wheremAgFis the mass of silver,

48、 in milligrams;VAgFis the volume, in millilitres, of potassium bromide solution at equivalence point.DIN EN ISO 11427:2016-12EN ISO 11427:2016 (E)7 The successive values of factor determinations shall not differ from each other by more than 0,05 % relative value. The mean value, F , shall be used in subsequent calculations for maximum accuracy. The potassium bromide factor sha