EN ISO 13904:2016

SLOVENSKI STANDARD
01-maj-2016
1DGRPHãþD
SIST EN ISO 13904:2005
.UPD'RORþHYDQMHWULSWRIDQD,62
Animal feeding stuffs - Determination of tryptophan content (ISO 13904:2016)
Futtermittel - Bestimmung des Tryptophangehalts (ISO 13904:2016)
Aliments des animaux - Détermination de la teneur en tryptophane (ISO 13904:2016)
Ta slovenski standard je istoveten z: EN ISO 13904:2016
ICS:
65.120 Krmila Animal feeding stuffs
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 13904
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2016
EUROPÄISCHE NORM
ICS 65.120 Supersedes EN ISO 13904:2005
English Version
Animal feeding stuffs - Determination of tryptophan
content (ISO 13904:2016)
Aliments des animaux - Dosage du tryptophane (ISO Futtermittel - Bestimmung des Tryptophangehalts (ISO
13904:2016) 13904:2016)
This European Standard was approved by CEN on 30 January 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 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, 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
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13904:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
European foreword
This document (EN ISO 13904:2016) has been prepared by Technical Committee ISO/TC 34 “Food
products" in collaboration with Technical Committee CEN/TC 327 “Animal feeding stuffs - Methods of
sampling and analysis” the secretariat of which is held by NEN.
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 September 2016, and conflicting national standards
shall be withdrawn at the latest by September 2016.
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 responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 13904:2005.
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, 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 Kingdom.
Endorsement notice
The text of ISO 13904:2016 has been approved by CEN as EN ISO 13904:2016 without any modification.

INTERNATIONAL ISO
STANDARD 13904
Second edition
2016-02-15
Animal feeding stuffs —
Determination of tryptophan content
Aliments des animaux — Dosage du tryptophane
Reference number
ISO 13904:2016(E)
©
ISO 2016
ISO 13904:2016(E)
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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ii © ISO 2016 – All rights reserved

ISO 13904:2016(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Principle . 1
3 Reagents and materials . 1
4 Apparatus . 3
5 Procedure. 4
5.1 Preparation of samples . 4
5.1.1 Feeding stuffs . 4
5.1.2 Commercial pure substances and premixtures containing more than 2 %
of tryptophan . 4
5.2 Determination of free tryptophan (extract) . 4
5.2.1 Feeding stuffs . 4
5.2.2 Commercial pure substances and premixtures containing more than 2 %
of tryptophan . 4
5.3 Determination of total tryptophan (hydrolysates) . 5
5.4 HPLC determination . 5
6 Calculation of results . 6
6.1 Feeding stuffs . 6
6.2 Commercial pure products and premixtures containing more than 2 % of tryptophan . 6
6.2.1 Control of the calibration. 6
6.2.2 Calculation . 6
7 Precision . 7
7.1 Interlaboratory test. 7
7.1.1 Feeding stuffs . 7
7.1.2 Commercial pure substances and premixtures containing more than 2 %
of tryptophan . 7
7.2 Repeatability . 7
7.2.1 Feeding stuffs . 7
7.2.2 Commercial pure substances and premixtures containing more than 2 %
of tryptophan . 7
7.3 Reproducibility . 7
7.3.1 Feeding stuffs . 7
7.3.2 Pure products and premixtures containing more than 2 % of tryptophan . 8
8 Test report . 8
Annex A (informative) Results of an interlaboratory test . 9
Annex B (informative) Observations on the method .11
Annex C (informative) Sample preparation: Example for analyses in pure products
and premixtures .12
Annex D (informative) Results of an interlaboratory test for tryptophan in pure products
and premixtures containing more than 2 % of tryptophan .13
Bibliography .14
ISO 13904:2016(E)
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 34, Food products, Subcommittee SC 10, Animal
feeding stuffs.
This s
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