SIST EN ISO 5983-1:2005

Animal feeding stuffs - Determination of nitrogen content and calculation of crude protein content - Part 1: Kjeldahl method (ISO 5983-1:2005)

ISO 5983-1:2005 specifies a method for the determination of the nitrogen content of animal feeding stuffs by the Kjeldahl process, and a method for the calculation of the crude protein content.
The method does not measure oxidized forms of nitrogen or heterocyclic nitrogen compounds.
This method does not distinguish between protein nitrogen and non-protein nitrogen. If it is important to determine the content of non-protein nitrogen, an appropriate method should be used.

Futtermittel - Bestimmung des Stickstoffgehaltes und Berechnung des Rohproteingahaltes - Teil 1: Kjeldahl-Verfahren (ISO 5983-1:2005)

Diese Internationale Norm legt ein Verfahren zur Bestimmung des Stickstoffgehaltes in Futtermitteln nach der Kjeldahl-Methode und ein Verfahren zur Berechnung des Rohproteingehaltes fest.
Dieses Verfahren unterscheidet nicht zwischen Proteinstickstoff und Nichtproteinstickstoff. Ist es von Bedeutung, den Gehalt des Nichtproteinstickstoffs zu bestimmen, muss ein geeignetes Verfahren ange-wendet werden.
ANMERKUNG   Unter bestimmten Verhältnissen ist mit diesem Verfahren eine vollständige Stickstoffrückgewinnung aus Nitraten und Nitriten nicht möglich.

Aliments des animaux - Détermination de la teneur en azote et calcul de la teneur en protéines brutes - Partie 1: Méthode Kjeldahl (ISO 5983-1:2005)

L'ISO 5983-1:2005 spécifie une méthode de dosage de l'azote dans les aliments pour animaux par la méthode de Kjeldahl, ainsi qu'une méthode pour le calcul de la teneur en protéines brutes.
Cette méthode ne mesure pas les formes oxydées de l'azote ou les composés azotés hétérocycliques.
Cette méthode ne fait pas la différence entre l'azote protéique et l'azote non protéique. S'il est nécessaire de déterminer la teneur en azote non protéique, il convient d'employer une méthode appropriée.

Krma - Določevanje dušika in izračun vsebnosti surovih beljakovin - 1. del: Kjeldahlova metoda (ISO 5983-1:2005)

General Information

• Status: Published
• Publication Date: 30-Sep-2005
• ICS: 65.120 - Animal feeding stuffs
• Technical Committee: KŽP - Agricultural food products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Oct-2005
• Due Date: 01-Oct-2005
• Completion Date: 01-Oct-2005
• Ref Project: EN ISO 5983-1:2005 - Animal feeding stuffs - Determination of nitrogen content and calculation of crude protein content - Part 1: Kjeldahl method (ISO 5983-1:2005)

Relations

• Replaces: SIST ISO 5983:2001 - Animal feeding stuffs -- Determination of nitrogen content and calculation of crude protein content -- Kjeldahl method
• Effective Date: 01-Dec-2012
• Corrected By: SIST EN ISO 5983-1:2005/AC:2009 - Animal feeding stuffs - Determination of nitrogen content and calculation of crude protein content - Part 1: Kjeldahl method (ISO 5983-1:2005/Cor 1:2008)
• Effective Date: 01-Jun-2009

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 5983-1:2005
01-oktober-2005
.UPD'RORþHYDQMHGXãLNDLQL]UDþXQYVHEQRVWLVXURYLKEHOMDNRYLQGHO
.MHOGDKORYDPHWRGD,62
Animal feeding stuffs - Determination of nitrogen content and calculation of crude protein
content - Part 1: Kjeldahl method (ISO 5983-1:2005)
Futtermittel - Bestimmung des Stickstoffgehaltes und Berechnung des
Rohproteingahaltes - Teil 1: Kjeldahl-Verfahren (ISO 5983-1:2005)
Aliments des animaux - Détermination de la teneur en azote et calcul de la teneur en
protéines brutes - Partie 1: Méthode Kjeldahl (ISO 5983-1:2005)
Ta slovenski standard je istoveten z: EN ISO 5983-1:2005
ICS:
65.120 Krmila Animal feeding stuffs
SIST EN ISO 5983-1:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD
EN ISO 5983-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2005
ICS 65.120

English Version
Animal feeding stuffs - Determination of nitrogen content and
calculation of crude protein content - Part 1: Kjeldahl method
(ISO 5983-1:2005)
Aliments des animaux - Détermination de la teneur en Futtermittel - Bestimmung des Stickstoffgehaltes und
azote et calcul de la teneur en protéines brutes - Partie 1: Berechnung des Rohproteingahaltes - Teil 1: Kjeldahl-
Méthode Kjeldahl (ISO 5983-1:2005) Verfahren (ISO 5983-1:2005)
This European Standard was approved by CEN on 27 June 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5983-1:2005: E
worldwide for CEN national Members.

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EN ISO 5983-1:2005 (E)





Foreword


This document (EN ISO 5983-1:2005) has been prepared by Technical Committee ISO/TC 34
"Agricultural 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 January 2006, and conflicting national
standards shall be withdrawn at the latest by January 2006.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.


Endorsement notice

The text of ISO 5983-1:2005 has been approved by CEN as EN ISO 5983-1:2005 without any
modifications.

2

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INTERNATIONAL ISO
STANDARD 5983-1
First edition
2005-07-01


Animal feeding stuffs — Determination of
nitrogen content and calculation of crude
protein content —
Part 1:
Kjeldahl method
Aliments des animaux — Détermination de la teneur en azote et calcul
de la teneur en protéines brutes —
Partie 1: Méthode Kjeldahl





Reference number
ISO 5983-1:2005(E)
©
ISO 2005

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ISO 5983-1:2005(E)
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ii © ISO 2005 – All rights reserved

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ISO 5983-1:2005(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Principle. 1
4 Reagents and materials . 1
5 Apparatus . 2
6 Sampling. 2
7 Preparation of test sample. 3
8 Procedure . 3
9 Calculation and expression of results. 5
10 Precision. 6
11 Test report . 7
Annex A (informative) Results of interlaboratory test. 8
Bibliography . 10

© ISO 2005 – All rights reserved iii

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ISO 5983-1:2005(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 5983-1 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 10, Animal
feeding stuffs.
This first edition of ISO 5983-1, together with ISO 5983-2:2005, cancels and replaces ISO 5983:1997, which
has been technically revised.
ISO 5983 consists of the following parts, under the general title Animal feeding stuffs — Determination of
nitrogen content and calculation of crude protein content:
 Part 1: Kjeldahl method
 Part 2: Block digestion/steam distillation method

iv © ISO 2005 – All rights reserved

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INTERNATIONAL STANDARD ISO 5983-1:2005(E)

Animal feeding stuffs — Determination of nitrogen content
and calculation of crude protein content —
Part 1:
Kjeldahl method
1 Scope
This part of ISO 5983 specifies a method for the determination of the nitrogen content of animal feeding stuffs
by the Kjeldahl process, and a method for the calculation of the crude protein content.
The method does not measure oxidized forms of nitrogen or heterocyclic nitrogen compounds.
This method does not distinguish between protein nitrogen and non-protein nitrogen. If it is important to
determine the content of non-protein nitrogen, an appropriate method should be used.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 6498, Animal feeding stuffs — Preparation of test samples
3 Principle
The organic matter is digested by sulfuric acid in the presence of a catalyst. The reaction product is rendered
alkaline, then the liberated ammonia is distilled and titrated. The nitrogen content is calculated and the result
is multiplied by the conventional factor to obtain the crude protein content.
4 Reagents and materials
Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or deionized water
or water of equivalent purity.
The reagents [except the standard materials (4.6)] shall be practically free from nitrogenous compounds.
4.1 Potassium sulfate.
4.2 Catalyst, either 4.2.1 or 4.2.2.
4.2.1 Copper(II) oxide (CuO).
4.2.2 Copper(II) sulfate pentahydrate (CuSO ·5H O).
4 2
4.3 Sulfuric acid, c(H SO ) = 18 mol/l, ρ (H SO ) = 1,84 g/ml.
2 4 20 2 4
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ISO 5983-1:2005(E)
4.4 Paraffin wax.
4.5 Saccharose.
4.6 Standard materials, either 4.6.1 or 4.6.2.
4.6.1 Acetanilide, with melting point 114 °C; nitrogen (N) content 103,6 g/kg.
4.6.2 Tryptophan, with melting point 282 °C; nitrogen (N) content 137,2 g/kg.
Dry before use.
4.7 Sodium hydroxide solution, w(NaOH) = 33 % (mass fraction).
4.8 Collecting liquid, either 4.8.1 or 4.8.2.
4.8.1 Sulfuric acid, standard volumetric solution, c(H SO ) = 0,05 mol/l or c(H SO ) = 0,125 mol/l.
2 4 2 4
4.8.2 Boric acid, ρ(H BO ) = 40 g/l.
3 3
4.9 Solutions for titration.
4.9.1 Sodium hydroxide, standard volumetric solution, c(NaOH) 0,1 mol/l or c(NaOH) = 0,25 mol/l.
4.9.2 Sulfuric acid, standard volumetric solution, c(H SO ) = 0,05 mol/l or c(H SO ) = 0,125 mol/l.
2 4 2 4
The molarity of standard volumetric solutions should be known to the fourth decimal point.
4.10 Mixed indicator, neutral point at pH 4,4 to 5,8.
Dissolve 2 g of methyl red and 1 g of methylene blue in 1 000 ml of ethanol [ϕ(C H OH) = 95 % (volume
2 5
fraction)].
4.11 pH indicator paper.
4.12 Boiling aids, such as granulated pumice stone, or glass beads of diameter 5 mm to 7 mm, or
carborundum chips, washed in hydrochloric acid and in distilled water, and ashed.
5 Apparatus
Usual laboratory apparatus and, in particular, the following.
5.1 Analytical balance.
5.2 Digestion, distillation and titration apparatus.
6 Sampling
A representative sample should have been sent to the laboratory. It should not have been damaged or
changed during transport or storage.
Sampling is not part of the method specified in this part of ISO 5893. A recommended sampling method is
given in ISO 6497.
Store the sample in such a way that deterioration and change in its composition are prevented.
2 © ISO 2005 – All rights reserved

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ISO 5983-1:2005(E)
7 Preparation of tes
...