ISO 13756:2015

INTERNATIONAL ISO
STANDARD 13756
Second edition
2015-02-01
Jewellery — Determination of
silver in silver jewellery alloys —
Volumetric (potentiometric) method
using sodium chloride or potassium
chloride
Joaillerie — Dosage de l’argent dans les alliages d’argent pour la
bijouterie-joaillerie — Méthode volumétrique (potentiométrique)
utilisant le chlorure de sodium ou le chlorure de potassium
Reference number
©
ISO 2015
© ISO 2015
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Reagents . 1
5 Apparatus . 2
6 Sampling . 2
7 Procedure. 2
7.1 Determination of sodium chloride or potassium chloride standard solution factor . 2
7.1.1 Preparation of silver standards . 2
7.1.2 Titration of standard silver solution . 2
7.1.3 Calculation of sodium chloride or potassium chloride standard solution factor . 3
7.2 Determination . 3
7.2.1 Preparation of the sample solution . 3
7.2.2 Elimination of palladium . 3
7.2.3 Titration of the sample solution . 3
8 Calculation and expression of results . 3
8.1 Calculation . 3
8.2 Repeatability . 4
9 Test report . 4
Bibliography . 5
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 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 matters 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 document 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 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 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 ISO’s 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 and replaces the first edition (ISO 13756:1997), which has been technically
revised with the following changes:
— addition of an analytical balance in Clause 5;
— change of requirement for sampling in Clause 6;
— addition of a warning in Clause 7 that suitable health and safety procedures should be followed;
— International Standard editorially revised.
iv © ISO 2015 – All rights reserved

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;
— “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 as 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 conveyi
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