SIST EN ISO 15512:2017
(Main)Plastics - Determination of water content (ISO 15512:2016)
Plastics - Determination of water content (ISO 15512:2016)
1.1 This International Standard specifies methods for the determination of the water content of plastics
in the form of powder, granules, and finished articles. These methods do not test for water absorption
(kinetics and equilibrium) of plastics as measured by ISO 62.
Method A is suitable for the determination of water content as low as 0,1 % with an accuracy of 0,1 %.
Method B and Method C are suitable for the determination of water content as low as 0,01 % with an
accuracy of 0,01 %.
Water content is an important parameter for processing materials and has to remain below the level
specified in the appropriate material standard.
1.2 Four alternative methods are specified in this International Standard.
— Method A is an extraction method using anhydrous methanol followed by a Karl Fischer titration
of the extracted water. It can be used for all plastics and is applicable to granules smaller than
4 mm × 4 mm × 3 mm. The method can also be used for, e.g. prepolymer materials in the form of a
powder that are insoluble in methanol.
— Method B1 is a vaporization method using a tube oven. The water contained in the test portion is
vaporized and carried to the titration cell by a dry air or nitrogen carrier gas, followed by a Karl
Fischer titration of the collected water. It can be used for all plastics and is applicable to granules
smaller than 4 mm × 4 mm × 3 mm.
— Method B2 is a vaporization method using a heated sample vial. The water contained in the test
portion is vaporized and carried to the titration cell by a dry air or nitrogen carrier gas, followed
by a Karl Fischer titration of the collected water. It can be used for all plastics and is applicable to
granules smaller than 4 mm × 4 mm × 3 mm.
— Method C is a manometric method. The water content is determined from the increase in pressure,
which results when the water is evaporated under a vacuum. This method is not applicable to plastic
samples containing volatile compounds, other than water, in amounts contributing significantly
to the vapour pressure at room temperature. Checks for the presence of large amounts of volatile
compounds are to be carried out periodically, for example by gas chromatography. Such checks are
particularly required for new types or grades of material.
Kunststoffe - Bestimmung des Wassergehaltes (ISO 15512:2016)
1.1 Diese Internationale Norm legt Verfahren zur Bestimmung des Wassergehalts von Kunststoffen fest, die als Pulver, Granulat oder Fertigerzeugnis vorliegen. Bei diesen Verfahren wird nicht, wie nach ISO 62, die Wasseraufnahme (Kinetik und Gleichgewicht) von Kunststoffen geprüft.
Verfahren A ist für die Bestimmung des Wassergehalts bis hinab zu 0,1 % mit einer Genauigkeit von 0,1 % geeignet. Verfahren B und C sind für die Bestimmung des Wassergehalts bis hinab zu 0,01 % mit einer Genauigkeit von 0,01 % geeignet.
Der Wassergehalt ist ein wichtiger Parameter bei der Verarbeitung von Werkstoffen und muss stets unter dem in den entsprechenden Werkstoffnormen festgelegten Wert bleiben.
1.2 In dieser Internationalen Norm sind vier alternative Verfahren festgelegt:
Verfahren A ist ein Extraktionsverfahren mit wasserfreiem Methanol und anschließender Titration des Wassers nach dem Karl-Fischer-Verfahren. Es kann für alle Kunststoffe verwendet werden und ist auf Granulate mit einer Korngröße kleiner als 4 mm × 4 mm × 3 mm anwendbar. Das Verfahren kann auch z. B. auf Vorpolymer-Pulvermaterialien angewendet werden, die in Methanol unlöslich sind.
Verfahren B1 ist ein Verdampfungsverfahren unter Anwendung eines Rohrofens. Das in der Analysenmenge enthaltene Wasser wird verdampft und durch trockene Luft oder Stickstoff als Träger-gas in die Titrationszelle überführt, in der anschließend die Titration des gesammelten Wassers nach dem Karl-Fischer-Verfahren erfolgt. Es kann für sämtliche Kunststoffe und Granulate angewendet werden, die kleiner als 4 mm × 4 mm × 3 mm sind.
Verfahren B2 ist ein Verdampfungsverfahren unter Anwendung eines erhitzten Probenfläschchens. Das in der Analysenmenge enthaltene Wasser wird verdampft und durch trockene Luft oder Stickstoff als Trägergas in die Titrationszelle überführt, in der anschließend die Titration des gesammelten Wassers nach dem Karl-Fischer-Verfahren erfolgt. Es kann für sämtliche Kunststoffe und Granulate angewendet werden, die kleiner als 4 mm × 4 mm × 3 mm sind.
Verfahren C ist ein manometrisches Verfahren. Der Wassergehalt wird aus dem Druckanstieg nach dem Verdampfen des Wassers unter Vakuum bestimmt. Das Verfahren kann nicht auf Kunststoffproben an¬gewendet werden, die andere flüchtige Bestandteile als Wasser in solchen Mengen enthalten, dass diese signifikant zum Dampfdruck bei Raumtemperatur beisteuern. In regelmäßigen Abständen sollte, z. B. durch Gaschromatographie, die Anwesenheit großer Mengen an flüchtigen Bestandteilen überprüft werden. Diese Überprüfungen sind besonders bei neuen Typen oder Klassen von Werkstoffen not¬wendig.
Plastiques - Dosage de l'eau (ISO 15512:2016)
1.1 ISO 15512:2016 spécifie des méthodes pour le dosage de l'eau dans les plastiques sous forme de poudre, de granulés et d'articles finis. Ces méthodes ne contrôlent pas l'absorption d'eau (cinétique et équilibre) des plastiques, cet aspect étant traité dans l'ISO 62.
La Méthode A est applicable au dosage de l'eau à des niveaux aussi faibles que 0,1 % avec une précision de 0,1 %. La Méthode B et la Méthode C sont applicables au dosage de l'eau à des niveaux aussi faibles que 0,01 % avec une précision de 0,01 %.
La teneur en eau est un paramètre important de la mise en ?uvre des matériaux et il convient qu'elle reste en dessous du niveau spécifié dans la norme de produit appropriée.
1.2 Quatre méthodes possibles sont spécifiées dans la présente Norme internationale.
? La méthode A consiste en une extraction de l'eau à l'aide de méthanol anhydre suivie d'un titrage de l'eau extraite par la méthode de Karl Fischer. Elle peut être utilisée pour tous les plastiques et est applicable aux granulés de moins de 4 mm × 4 mm × 3 mm. Elle peut également être utilisée, par exemple, pour les poudres de prépolymère insolubles dans le méthanol.
? La méthode B1 procède par vaporisation dans un four tubulaire. L'eau contenue dans la prise d'essai est transformée en vapeur, qui est transférée à l'aide d'un gaz vecteur d'air sec ou d'azote dans la cuve de titrage, l'eau recueillie est ensuite titrée par la méthode de Karl Fischer. Cette méthode peut être utilisée pour tous les plastiques et est applicable aux granulés de moins de 4 mm × 4 mm × 3 mm.
? La méthode B2 procède par vaporisation dans un flacon d'échantillon chauffé. L'eau contenue dans la prise d'essai est transformée en vapeur, qui est transférée à l'aide d'un gaz vecteur d'air sec ou d'azote dans la cuve de titrage, l'eau recueillie est ensuite titrée par la méthode de Karl Fischer. Cette méthode peut être utilisée pour tous les plastiques et est applicable aux granulés de moins de 4 mm × 4 mm × 3 mm.
? La méthode C est une méthode manométrique. Le dosage de l'eau se fonde sur l'augmentation de pression après évaporation de l'eau sous vide. Cette méthode n'est pas applicable aux échantillons de plastiques contenant des composés volatils, autres que l'eau, en quantité suffisante pour avoir un effet significatif sur la pression de vapeur à température ambiante. Il convient d'effectuer périodiquement des vérifications de la présence de grandes quantités de composés volatils, par exemple par chromatographie en phase gazeuse. Ces vérifications sont particulièrement nécessaires pour les nouveaux types ou les nouvelles qualités de matériaux.
Polimerni materiali - Določevanje vode (ISO 15512:2016)
1.1 Ta mednarodni standard določa metode za določevanje vode v polimernih materialih v obliki praškov, granul in dokončanih izdelkov. Te metode ne preskušajo absorpcije vode (kinetika in ravnovesje) polimernih materialov, kot se meri v skladu s standardom ISO 62.
Metoda A je primerna za določevanje vsebnosti vode, ki dosega komaj 0,1 %, z natančnostjo 0,1 %.
Metoda B in metoda C sta primerni za določevanje vsebnosti vode, ki dosega komaj 0,01 %, z
natančnostjo 0,01 %.
Vsebnost vode je pomemben parameter za obdelavo materialov in mora ostati pod ravnjo, določeno v ustreznem standardu za materiale.
1.2 V tem mednarodnem standardu so določene štiri alternativne metode.
– Metoda A je metoda ekstrakcije z brezvodnim metanolom, ki mu sledi titracija ekstrahirane vode po Karlu Fischerju. Uporabiti jo je mogoče za vse polimerne elemente in velja za granule, manjše od 4 mm × 4 mm × 3 mm. Metoda se lahko uporablja tudi npr. za predpolimerne materiale v obliki praška, ki niso topni v metanolu.
– Metoda B1 je metoda izparevanja s cevasto pečjo. Voda v preskusni količini
izpari in se prenese v titracijsko celico prek nosilnega plina (suh zrak ali dušik), čemur sledi titracija zbrane vode po Karlu Fischerju. Uporabiti jo je mogoče za vse polimerne elemente in velja za granule, manjše od 4 mm × 4 mm × 3 mm.
– Metoda B je metoda izparevanja z ogrevano preskusno stekleničko. Voda v preskusni količini izpari in se prenese v titracijsko celico prek nosilnega plina (suh zrak ali dušik), čemur sledi titracija zbrane vode po Karlu Fischerju. Uporabiti jo je mogoče za vse polimerne elemente in velja za granule, manjše od 4 mm × 4 mm × 3 mm.
– Metoda C je manometrska metoda. Vsebnost vode se določi na podlagi povečanja tlaka, do katerega pride, ko voda izhlapi v vakuumu. Ta metoda se ne uporablja za vzorce polimernih materialov, ki vsebujejo hlapne spojine, ki niso voda, v količinah, ki znatno prispevajo k parnemu tlaku pri sobni temperaturi. Redno je treba preverjati prisotnost velikih količin hlapnih spojin, na primer s plinsko kromatografijo. Tako preverjanje je zlasti potrebno za nove tipe ali razrede materiala.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 15512:2017
01-januar-2017
1DGRPHãþD
SIST EN ISO 15512:2014
3ROLPHUQLPDWHULDOL'RORþHYDQMHYRGH ,62
Plastics - Determination of water content (ISO 15512:2016)
Kunststoffe - Bestimmung des Wassergehaltes (ISO 15512:2016)
Plastiques - Dosage de l'eau (ISO 15512:2016)
Ta slovenski standard je istoveten z: EN ISO 15512:2016
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 15512:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 15512:2017
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SIST EN ISO 15512:2017
EN ISO 15512
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2016
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 15512:2014
English Version
Plastics - Determination of water content (ISO
15512:2016)
Plastiques - Dosage de l'eau (ISO 15512:2016) Kunststoffe - Bestimmung des Wassergehaltes (ISO
15512:2016)
This European Standard was approved by CEN on 29 September 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 15512:2016 E
worldwide for CEN national Members.
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SIST EN ISO 15512:2017
EN ISO 15512:2016 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 15512:2017
EN ISO 15512:2016 (E)
European foreword
This document (EN ISO 15512:2016) has been prepared by Technical Committee ISO/TC 61 “Plastics”
in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by
NBN.
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 May 2017, and conflicting national standards shall be
withdrawn at the latest by May 2017.
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 15512:2014.
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 15512:2016 has been approved by CEN as EN ISO 15512:2016 without any modification.
3
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SIST EN ISO 15512:2017
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SIST EN ISO 15512:2017
INTERNATIONAL ISO
STANDARD 15512
Fourth edition
2016-10-15
Plastics — Determination of water
content
Plastiques — Dosage de l’eau
Reference number
ISO 15512:2016(E)
©
ISO 2016
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SIST EN ISO 15512:2017
ISO 15512:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© 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
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
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Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved
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SIST EN ISO 15512:2017
ISO 15512:2016(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Method A — Extraction with anhydrous methanol . 1
3.1 Principle . 1
3.2 Reagents. 2
3.3 Apparatus . 2
3.4 Preparation of test sample . 2
3.4.1 Granules or powder . 2
3.4.2 Finished articles . 2
3.5 Procedure . 3
3.5.1 Precautions . 3
3.5.2 Preparation of test portions . 3
3.5.3 Determination . 3
3.6 Expression of results . 3
3.7 Precision . 4
4 Method B1 — Water vaporization using a heating tube oven . 4
4.1 Principle . 4
4.2 Reagents. 4
4.3 Apparatus . 5
4.4 Preparation of test sample . 7
4.5 Procedure . 7
4.5.1 Precautions . 7
4.5.2 Preparation of apparatus . 7
4.5.3 Equipment check . 7
4.5.4 Determination . 8
4.6 Expression of results . 8
4.7 Precision . 9
5 Method B2 — Water vaporization using a heated sample vial . 9
5.1 Principle . 9
5.2 Reagents. 9
5.3 Apparatus .10
5.4 Preparation of test sample .11
5.5 Procedure .12
5.5.1 Preparation of apparatus .12
5.5.2 Equipment check .12
5.5.3 Determination .12
5.6 Expression of results .14
5.7 Precision .14
6 Method C — Manometric method .15
6.1 Principle .15
6.2 Reagents.15
6.3 Apparatus .15
6.4 Preparation of test sample .16
6.5 Procedure .16
6.5.1 Equipment .16
6.5.2 Outgassing .17
6.5.3 Calibration .17
6.5.4 Determination .19
6.6 Expression of results .20
6.7 Precision .20
© ISO 2016 – All rights reserved iii
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SIST EN ISO 15512:2017
ISO 15512:2016(E)
7 Test report .20
Annex A (informative) Alternative sample preparation methods and titration methods .21
Annex B (informative) Selection of the optimum heating temperature for the water
content determination .22
Annex C (normative) Determination of the water content of a water standard .24
Bibliography .25
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SIST EN ISO 15512:2017
ISO 15512:2016(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 World Trade Organization (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 61, Plastics, Subcommittee SC 5, Physical-
chemical properties.
This fourth edition cancels and replaces the third edition (ISO 15512:2014), of which it constitutes a
minor revision to update information in 6.2.1.
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SIST EN ISO 15512:2017
ISO 15512:2016(E)
Introduction
The interlaboratory comparability of the water content determination of plastics is often low. Major
causes for this are the sample packaging, sample handling, and differences between equipment and
settings. Samples have to, e.g. be packed in special glass containers or water barrier sealed bags.
Sample handling is preferably to be carried out in a dry nitrogen or air environment. For improving the
repeatability and reproducibility, the procedure prescribed in this International Standard is intended
to be followed strictly.
The temperature settings for the vaporization method are not specified in this International Standard.
For the manometric method, a temperature of 200 °C is often used. However, for some condensation
materials, this might be too high and could, e.g. cause generation of water due to a condensation
reaction.
The heating temperature has to be optimized concerning the material to be tested, the equipment in
use, and the practical circumstances. If the temperature is too low, the total amount of water in the
material to be tested will not be evaporated completely, whereas too high temperatures cause water
generation due to effects like degradation and condensation reactions.
In this International Standard, a procedure is included for optimization of the heating temperature
in order to choose the correct temperature for the water content determination and to improve the
interlaboratory comparability.
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SIST EN ISO 15512:2017
INTERNATIONAL STANDARD ISO 15512:2016(E)
Plastics — Determination of water content
1 Scope
1.1 This International Standard specifies methods for the determination of the water content of plastics
in the form of powder, granules, and finished articles. These methods do not test for water absorption
(kinetics and equilibrium) of plastics as measured by ISO 62.
Method A is suitable for the determination of water content as low as 0,1 % with an accuracy of 0,1 %.
Method B and Method C are suitable for the determination of water content as low as 0,01 % with an
accuracy of 0,01 %.
Water content is an important parameter for processing materials and has to remain below the level
specified in the appropriate material standard.
1.2 Four alternative methods are specified in this International Standard.
— Method A is an extraction method using anhydrous methanol followed by a Karl Fischer titration
of the extracted water. It can be used for all plastics and is applicable to granules smaller than
4 mm × 4 mm × 3 mm. The method can also be used for, e.g. prepolymer materials in the form of a
powder that are insoluble in methanol.
— Method B1 is a vaporization method using a tube oven. The water contained in the test portion is
vaporized and carried to the titration cell by a dry air or nitrogen carrier gas, followed by a Karl
Fischer titration of the collected water. It can be used for all plastics and is applicable to granules
smaller than 4 mm × 4 mm × 3 mm.
— Method B2 is a vaporization method using a heated sample vial. The water contained in the test
portion is vaporized and carried to the titration cell by a dry air or nitrogen carrier gas, followed
by a Karl Fischer titration of the collected water. It can be used for all plastics and is applicable to
granules smaller than 4 mm × 4 mm × 3 mm.
— Method C is a manometric method. The water content is determined from the increase in pressure,
which results when the water is evaporated under a vacuum. This method is not applicable to plastic
samples containing volatile compounds, other than water, in amounts contributing significantly
to the vapour pressure at room temperature. Checks for the presence of large amounts of volatile
compounds are to be carried out periodically, for example by gas chromatography. Such checks are
particularly required for new types or grades of material.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 760, Determination of water — Karl Fischer method (General method)
3 Method A — Extraction with anhydrous methanol
3.1 Principle
A test portion is extracted with anhydrous methanol and the extracted water determined by titration
using the Karl Fischer method.
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SIST EN ISO 15512:2017
ISO 15512:2016(E)
3.2 Reagents
During the analysis, use only reagents of recognized analytical grade.
3.2.1 Titration medium, methanol anhydrous, having a water content less than 0,1 % by mass. Other
solvents can be used if shown to be comparable.
3.2.2 Karl Fischer reagent, with an equivalence factor of approximately 3 mg/ml to 5 mg/ml of water.
When the reagent is prepared, check its equivalence factor as specified in ISO 760.
3.3 Apparatus
Ordinary laboratory apparatus and the following.
3.3.1 Glass flasks, approximately 250 ml capacity, provided with a suitable cap preventing moisture
uptake or release.
3.3.2 Conical titration flasks, approximately 150 ml capacity, with standard ground necks and
provided with ground-glass stoppers.
3.3.3 Reflux condensers, with ground neck capable of being fitted on to the flasks (3.3.2) and on to
the tubes (3.3.4).
3.3.4 Water-absorption tubes with ground joints, containing calcium chloride or other suitable
drying agent.
3.3.5 Heaters, suitable for the conical titration flasks (3.3.2).
3.3.6 Desiccator, containing a suitable desiccant.
3.3.7 Analytical balance, accurate to 0,2 mg.
3.3.8 Karl Fischer apparatus, for determining water content in accordance with ISO 760.
3.4 Preparation of test sample
3.4.1 Granules or powder
Take a representative sample of approximately 100 g. Put the sample into a pre-dried glass flask (3.3.1)
and immediately close it with a stopper.
NOTE It is desirable to pre-dry the container in an oven and then cool it over a suitable desiccant.
3.4.2 Finished articles
Cut or saw the sample into pieces of appropriate size, i.e. having a maximum size of 4 mm × 4 mm × 3 mm.
Proceed quickly to minimize moisture absorption.
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SIST EN ISO 15512:2017
ISO 15512:2016(E)
3.5 Procedure
3.5.1 Precautions
Due to the low quantities of water measured, maximum care shall be exercised at all times to avoid
contaminating the sample with water from the sample container, the atmosphere, or transfer
equipment. Hygroscopic resin samples shall be protected from the atmosphere.
3.5.2 Preparation of test portions
Conduct the test on two test portions from the same sample. Use test portions containing 10 mg to
20 mg of water based on the estimated water content of the sample.
Using modern coulometric Karl Fischer titration instruments test portions containing less than 10 mg
can be applied if the same level of accuracy of results can be achieved.
3.5.3 Determination
Carefully dry the apparatus.
Weigh each test portion to the nearest 1 mg into a conical titration flask (3.3.2) fitted with a ground-
glass stopper. Pipette 50 ml of anhydrous methanol (3.2.1) into the conical flask containing the test
portion. At the same time, pipette 50 ml of anhydrous methanol to another conical flask for a blank test.
Stopper the flasks. Keep the stoppered flasks in the desiccator (3.3.6) pending continuation of the test.
Unstopper the flasks and quickly attach them to reflux condensers (3.3.3) fitted with calcium chloride
tubes (3.3.4). Reflux the contents of the conical flasks for 3 h, then leave them for 45 min to cool to
room temperature. Separate the flasks from the condensers, quickly stopper them, and place them in
the desiccator.
Use the Karl Fischer apparatus (3.3.8) to titrate the contents of each flask with Karl Fischer reagent
(3.2.2).
NOTE Alternative sample preparation methods and titration methods are given in Annex A.
3.6 Expression of results
The water content, w, expressed as a percentage by mass, for each of the two determinations is given by
Formula (1):
VV− ×T
()
12
(1)
w= ×100
m
where
V is the volume, expressed in millilitres, of Karl Fischer reagent used for the determination;
1
V is the volume, expressed in millilitres, of Karl Fischer reagent used for the blank test;
2
T is the water equivalent, expressed in grams of water per millilitre of reagent, of Karl Fischer
reagent;
m is the mass, in grams, of the test portion.
NOTE For some equipment, V might not be available separately but only used for internal calculation of
2
V - V . In this case, the numerator in the formula simplifies to V × T.
1 2
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SIST EN ISO 15512:2017
ISO 15512:2016(E)
The two values for the water content shall not differ by more than 10 % relative or 0,02 % absolute,
whichever is the greater. If the difference is greater, repeat the measurements until acceptable
consecutive values are obtained and discard all unacceptable results.
The result is expressed as the average of these two determinations, rounded to the nearest 0,01 %
by mass.
3.7 Precision
The precision of this test method is not known because interlaboratory data are not available. If and
when interlaboratory data are obtained, a precision statement will be added to a subsequent revision.
For comparison of data between two laboratories, special care needs to be taken on sample packing
and sample handling.
4 Method B1 — Water vaporization using a heating tube oven
4.1 Principle
The sample is weighed then placed in an oven. The water contained in the test portion is vaporized
and carried to the titration cell by a dry nitrogen carrier gas. The water is then titrated using the
coulometric Karl Fischer method. This method is based on the reduction of iodine by sulfur dioxide in
the presence of water to form sulfur trioxide and hydroiodic acid as follows:
I + SO + H O → 2HI + SO
2 2 2 3
Unlike the conventional Karl Fischer reagents that include iodine, the coulometric technique generates
the iodine electrolytically from iodide:
− −
2I → I + 2e
2
with 10,71 C of generating current corresponding to 1 mg of water in accordance with Faraday’s Law.
4.2 Reagents
During the analysis, use only reagents of recognized analytical grade.
4.2.1 Anode solutio
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