EN ISO 8534:2008

SLOVENSKI STANDARD
01-januar-2009
1DGRPHãþD
SIST ISO 8534:1998
äLYDOVNHLQUDVWOLQVNHPDãþREHLQROMD'RORþHYDQMHYRGH.DUO)LVFKHUMHYD
PHWRGDEUH]SLULGLQD,62
Animal and vegetable fats and oils - Determination of water content - Karl Fischer
method (pyridine free) (ISO 8534:2008)
Tierische und pflanzliche Fette und Öle - Bestimmung des Wassergehalts - Karl-Fischer-
Verfahren (pyridinfrei) (ISO 8534:2008)
Corps gras d'origines animale et végétale - Détermination de la teneur en eau - Méthode
de Karl Fischer (sans pyridine) (ISO 8534:2008)
Ta slovenski standard je istoveten z: EN ISO 8534:2008
ICS:
67.200.10 5DVWOLQVNHLQåLYDOVNH Animal and vegetable fats
PDãþREHLQROMD and oils
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 8534
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2008
ICS 67.200.10
English Version
Animal and vegetable fats and oils - Determination of water
content - Karl Fischer method (pyridine free) (ISO 8534:2008)
Corps gras d'origines animale et végétale - Détermination Tierische und pflanzliche Fette und Öle - Bestimmung des
de la teneur en eau - Méthode de Karl Fischer (sans Wassergehalts - Karl-Fischer-Verfahren (pyridinfrei) (ISO
pyridine) (ISO 8534:2008) 8534:2008)
This European Standard was approved by CEN on 4 June 2008.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, 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
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8534:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3

Foreword
This document (EN ISO 8534:2008) has been prepared by Technical Committee ISO/TC 34 "Agricultural food
products" in collaboration with Technical Committee CEN/TC 307 “Oilseeds, vegetable and animal fats and
oils and their by-products - Methods of sampling and analysis” the secretariat of which is held by AFNOR.
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 2009, and conflicting national standards shall be withdrawn at
the latest by January 2009.
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.
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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 8534:2008 has been approved by CEN as a EN ISO 8534:2008 without any modification.

INTERNATIONAL ISO
STANDARD 8534
Second edition
2008-07-01
Animal and vegetable fats and oils —
Determination of water content — Karl
Fischer method (pyridine free)
Corps gras d'origines animale et végétale — Détermination de la teneur
en eau — Méthode de Karl Fischer (sans pyridine)

Reference number
ISO 8534:2008(E)
©
ISO 2008
ISO 8534:2008(E)
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ii © ISO 2008 – All rights reserved

ISO 8534:2008(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 8534 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal
and vegetable fats and oils.
This second edition cancels and replaces the first edition (ISO 8534:1996), which has been technically revised.
ISO 8534:2008(E)
Introduction
The determination of the water content of fats and oils according to Karl Fischer is carried out by two different
procedures. This International Standard specifies the volumetric Karl Fischer method for the determination of
higher milligram levels of water (high level moisture). It is used for samples having between 1 mg and 100 mg
of water in the sample.
Annex B specifies a coulometric titration, which requires between 10 µg and 10 mg water in the sample. The
coulometric method is more sensitive than the volumetric method and permits the determination of lower
water contents.
iv © ISO 2008 – All rights reserved

INTERNATIONAL STANDARD ISO 8534:2008(E)

Animal and vegetable fats and oils — Determination of water
content — Karl Fischer method (pyridine free)
1 Scope
This International Standard specifies a method for the determination of the water content of animal and
vegetable fats and oils (hereinafter referred to as fats) using Karl Fischer apparatus and a reagent which is
free of pyridine.
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 661, Animal and vegetable fats and oils — Preparation of test sample
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
water content
mass, in grams per 100 g of sample, of water as determined in accordance with the method specified in this
International Standard
NOTE The water content is expressed as a percentage mass fraction.
4 Principle
Dissolved fat is titrated against an iodine solution and sulfur dioxide (SO ) is oxidized by iodine in the
presence of water. In principle, the chemical reaction in Equation (1) takes place:
H O + I + SO + CH OH + 3RN → [RNH]SO CH + 2[RNH]I (1)
2 2 2 3 4 3
The alcohol reacts with SO and a nitrogenous base (RN) to form an intermediate alkylsulfite salt, which is
then oxidized by iodine to an alkylsulfate salt. This oxidation reaction consumes water contained in the sample.
The end point is monitored potentiometrically.
5 Reagents
WARNING — Comply with any local regulations which specify the handling of hazardous substances.
Technical, organizational and personal safety measures shall be followed.
It is recommended that “ready for use” working solvents be used, either one-component reagents (5.1.1) or
two-component reagents (5.1.2). Reagents with a titre of 1 mg and 2 mg water per millilitre are required for
acceptable performance.
ISO 8534:2008(E)
5.1 Karl Fischer reagents, consist of one-component reagents or two-component reagents for volumetric
determination.
5.1.1 One-component reagents, contain all the reactant in the titrant solution: iodine, sulfur dioxide, and
imidazole, dissolved in a suitable alcohol. Methanol is typically used as the working medium in the titration cell.
Absolute methanol is the solvent of choice. But for fats and oils, use a mixture of absolute methanol and
absolute chloroform (the methanol content should be at least 25 % volume fraction, or optimally 50 % volume
fraction).
5.1.2 Two-component reagents, consist of all necessary reactants for the titration, but in two different
solutions. The titrating agent (usually known as the titrant) contains only iodine and methanol, while the
solvent containing the other Karl Fischer reaction components is used as the working medium in the titration
cell.
5.2 Water standard, commercially prepared standard with a certified concentration of 10 mg/g (1,0 % mass
fraction).
6 Apparatus
Usual laboratory apparatus and, in particular the following.
6.1 Karl Fischer apparatus, set up according to the manufacturer's recommendations for the
determination of water in fats and oils. Set up and conduct protocols for routine maintenance as
recommended by the manufacturer. Use an airtight vessel and do not place the instrument in high humidity
areas. Do not place instruments or handle samples near water sources such as taps, sinks, and dishwashers
in the laboratory.
6.2 Analytical balance, readable to the nearest 0,1 mg.
6.3 Syringes, of capacity 1 ml, 2 ml, 5 ml, 10 ml, and 20 ml.
To ensure accurate and reproducible results from the water standard, use a glass gastight syringe. For water
standard 10,0, use a 10 ml syringe, and for either the water standard 1,00 or 0,10, use a 5 ml syringe. In
addition to the appropriate size syringe, use a needle that is long enough to allow for a subsurface injection
when injecting through the instrument's septum.
7 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 International Standard. A recommended sampling method
is given in ISO 5555.
8 Preparation of the test sample
Prepare the test sample in accordance with ISO 661.
The determination of water is conducted by adjusting the sample size to have between 1 mg and 100 mg
water for the volumetric titration (the main body of this International Standard) and between 10 µg and 10 mg
for the coulometric titration (Annex B) using Karl Fischer instruments and reagents which have been validated
with standard water solutions over the necessary range. For the volumetric determination, a minimum amount
of 0,5 ml Karl Fischer reagent shall be used for the titration.
2 © ISO 2008 – All rights reserved

ISO 8534:2008(E)
9 Procedure
9.1 Titre
The titre shall be determined daily for each bottle of titrant.
9.1.1 Prepare the instrument according to the manufacturer's recommendations for calibration.
9.1.2 Add 20 ml to 40 ml of working solvent (5.1) to the titration vessel. The solvent should cover the
platinum electrodes.
9.1.3 Titrate the vessel to a stable dry endpoint.
CAUTION — Take care not to overtitrate.
9.1.4 Determine the titre of the titrant using the water standard (5.2) and a syringe (6.3). Sample mass is
determined by difference.
9.1.4.1 Weigh, to the
...