EN ISO 23649:2025

SLOVENSKI STANDARD
01-maj-2025
Kemikalije za industrijo strojenja usnja - Določanje ciklosiloksanov v
hidroizolacijskih maščobnih sredstvih (ISO 23649:2025)
Chemicals for the leather tanning industry - Determination of cyclosiloxanes in
waterproofing fatliquors (ISO 23649:2025)
Chemikalien für die Ledergerbereiindustrie - Bestimmung von Cyclosiloxanen in
Imprägnierfettungsmitteln (ISO 23649:2025)
Produits chimiques pour l’industrie du tannage du cuir - Détermination des cyclosiloxan
(ISO 23649:2025)
Ta slovenski standard je istoveten z: EN ISO 23649:2025
ICS:
59.140.30 Usnje in krzno Leather and furs
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 23649
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2025
EUROPÄISCHE NORM
ICS 59.140.30
English Version
Chemicals for the leather tanning industry - Determination
of cyclosiloxanes (ISO 23649:2025)
Produits chimiques pour l'industrie du tannage du cuir Chemikalien für die Ledergerbereiindustrie -
- Détermination des cyclosiloxan (ISO 23649:2025) Bestimmung von Cyclosiloxanen in
Imprägnierfettungsmitteln (ISO 23649:2025)
This European Standard was approved by CEN on 24 February 2025.

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 standards 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 notified 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 23649:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 23649:2025) has been prepared by Technical Committee ISO/IULTCS
"International Union of Leather Technologists and Chemists Societies" in collaboration with Technical
Committee CEN/TC 289 “Leather” the secretariat of which is held by UNI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2025, and conflicting national standards shall
be withdrawn at the latest by August 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 23649:2025 has been approved by CEN as EN ISO 23649:2025 without any modification.

International
Standard
ISO
IULTCS
IUC 444
First edition
Chemicals for the leather tanning
2025-02
industry — Determination of
cyclosiloxanes
Produits chimiques pour l’industrie du tannage du cuir —
Détermination des cyclosiloxanes
Reference numbers
ISO 23649:2025(en)
IULTCS/IUC 444:2025(en) © ISO 2025

ISO 23649:2025(en)
IULTCS/IUC 444:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 23649:2025(en)
IULTCS/IUC 444:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Reagents . 2
7 Sampling and sample preparation . 3
8 Procedure . 3
8.1 Sample solution preparation .3
8.2 Liquid-liquid extraction.3
8.3 Instrumental analysis .4
9 Expression of results . 4
10 Precision . 4
11 Test report . 4
Annex A (informative) Chromatographic analysis operating parameters for GC-MS . 6
Annex B (informative) Precision: reliability of the method . 7
Annex C (normative) Sample preparation for non-water-soluble chemicals . 8
Bibliography . 9

iii
ISO 23649:2025(en)
IULTCS/IUC 444:2025(en)
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
IULTCS, originally formed in 1897, is a world-wide organization of professional leather societies to further
the advancement of leather science and technology. IULTCS has three Commissions, which are responsible
for establishing international methods for the sampling and testing of leather. ISO recognizes IULTCS as an
international standardizing body for the preparation of test methods for leather.
This document was prepared by the Chemical Test Commission of the International Union of Leather
Technologists and Chemists Societies (IUC Commission, IULTCS), in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO 23649:2025(en)
IULTCS/IUC 444:2025(en)
Introduction
This document includes a procedure for analysing certain cyclosiloxanes using gas chromatography (GC)
with mass spectrometer (MS) equipment. With this analytical method octamethylcyclotetrasiloxane (D4),
decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) can be determined.
In the leather industry cyclosiloxanes (D4), (D5) and (D6) are used in the manufacture of silicone-based
waterproofing fatliquors and can also be used in the production of silicone-based finishing chemicals
especially as handle modifiers.
At present, the official classification recognised in the EU is the following.
[1]
— Octamethylcyclotetrasiloxane (D4) is classified as persistent, bioaccumulative and toxic.
[2]
— Decamethylcyclopentasiloxane (D5) is classified as persistent, bioaccumulative and toxic.
[3]
— Dodecamethylcyclohexasiloxane (D6) is classified as persistent, bioaccumulative and toxic.
...