ISO 7102:2024

International
Standard
ISO 7102
IDF 257
First edition
Infant formula — Determination
2024-08
of β-galactooligosaccharides —
Ultra high performance liquid
chromatography (UHPLC) with
fluorescence detection after
pre-column derivatization
Préparation pour nourrissons — Détermination de la teneur
en β-galacto-oligosaccharides — Chromatographie liquide à
ultra-haute performance (CLUHP) couplée à une détection par
fluorescence après dérivation précolonne
Reference numbers
IDF 257:2024(en) © ISO and IDF 2024

IDF 257:2024(en)
© ISO and IDF 2024
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 International Dairy Federation
CP 401 • Ch. de Blandonnet 8 Silver Building • Bd Auguste Reyers 70/B
CH-1214 Vernier, Geneva B-1030 Brussels
Phone: +41 22 749 01 11 Phone: +32 2 325 67 40
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Published in Switzerland
ii
IDF 257:2024(en)
Contents Page
Forewords .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Chemicals and reagents . 2
5.1 List of chemicals and reagents .2
5.2 Preparation of reagents .3
5.3 Preparation of mobile phases .4
5.4 Preparation of standard solutions .4
6 Apparatus . 4
7 Procedure . 5
7.1 Sample preparation .5
7.1.1 Powdered or concentrated products on a ready-to feed (RTF) basis .5
7.1.2 Reconstituted products as prepared in 7.1.1 or products sold as RTF .6
7.1.3 Homogeneous powdered products without prior reconstitution .6
7.1.4 Calibration curve.6
7.1.5 Dextran ladder .6
7.1.6 Hydrolysis of maltodextrins and GOS .6
7.1.7 Reagent blank .6
7.1.8 Internal standard addition .6
7.1.9 Derivatization .6
7.1.10 Dilution .7
7.2 Chromatographic conditions .7
7.3 System suitability test .7
7.4 Calibration .7
8 Calculation . 8
9 Precision data . 8
9.1 General .8
9.2 Repeatability .9
9.3 Reproducibility .9
10 Test report . 9
Annex A (normative) Assessment of maltotriose concentration .10
Annex B (informative) Determination of molecular weight using dextran ladder .12
Annex C (informative) Determination of molecular weight using LC-MS .13
Annex D (informative) Example chromatograms .15
Annex E (informative) Precision data . 17
Bibliography . 19

iii
IDF 257:2024(en)
Forewords
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 document 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.
This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and
milk products, and the International Dairy Federation (IDF), in collaboration with AOAC INTERNATIONAL. It
is being published jointly by ISO and IDF and separately by AOAC INTERNATIONAL. The method described
in this document is equivalent to the AOAC Official Method 2021.01.
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
IDF 257:2024(en)
IDF (the International Dairy Federation) is a non-profit private sector organization representing the
interests of various stakeholders in dairying at the global level. IDF members are organized in National
Committees, which are national associations composed of representatives of dairy-related national interest
groups including dairy farmers, dairy processing industry, dairy suppliers, academics and governments/
food control authorities.
ISO and IDF collaborate closely on all matters of standardization relating to methods of analysis and
sampling for milk and milk products. Since 2001, ISO and IDF jointly publish their International Standards
using the logos and reference numbers of both organizations.
IDF draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IDF 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, IDF 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. IDF 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.
This document was prepared by the IDF Standing Committee on Analytical Methods for Composition
and ISO Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, in
collaboration with AOAC INTERNATIONAL. It is being published jointly by ISO and IDF and separately by
AOAC INTERNATIONAL. The method described in this document is equivalent to the AOAC Official Method
2021.01.
The work was carried out by the IDF/ISO Action Team on C42 of the Standing Committee on Analytical
Methods for Composition under the aegis of its project leader Mr S. Austin (CH).

v
International Standard
IDF 257:2024(en)
Infant formula — Determination of β-galactooligosaccharides
— Ultra high performance liquid chromatography (UHPLC)
with fluorescence detection after pre-column derivatization
1 Scope
This document specifies a method for the determination of β-galactooligosaccharides (GOS) in infant
formula (both powder and liquid) containing 0,2 g/100 g to 3,0 g/100 g of GOS in the product as prepared
ready for consumption.
The method has been validated in a multi-laboratory study with rec
...