EN ISO 15512:2019
(Main)Plastics - Determination of water content (ISO 15512:2019)
Plastics - Determination of water content (ISO 15512:2019)
This document 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 %. Method D is suitable for the determination of water content as low as 0,01 % with an accuracy of 0,01 %. Method E is suitable for the determination of water content as low as 0,001 % with an accuracy of 0,001 %. The stated accuracies are detection limits which depend also on the maximal possible sample mass. The water content is expressed as a percentage mass fraction of water.
Method D is suitable for polyamide (PA), polycarbonate (PC), polypropylene (PP), polyethylene (PE), epoxy resin, polyethylene terephthalate (PET), polyester, polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polylactide (PLA), polyamidimid (PAI), it is especially not recommended for samples which can release NH3. Methods A, B, C and E are generally suitable for all types of plastic and moisture level.
Water content is an important parameter for processing materials and is expected to remain below the level specified in the appropriate material standard.
Six alternative methods are specified in this document.
— 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 or a coulometric determination by means of a moisture sensor 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.
— Method D is a thermocoulometric method using a diphosphorus pentoxide (P2O5) cell for the detection of the vaporized water. The water contained in the test portion is vaporized and carried to the sensor cell by a dry air or nitrogen carrier gas, followed by a coulometric determination of the collected water. This method is not applicable to plastic sa
Kunststoffe - Bestimmung des Wassergehaltes (ISO 15512:2019)
Dieses Dokument 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 Messunsicherheit von 0,1 % geeignet. Verfahren B und C sind für die Bestimmung des Wassergehalts bis hinab zu 0,01 % mit einer Messunsicherheit von 0,01 % geeignet. Verfahren D ist für die Bestimmung des Wassergehalts bis hinab zu 0,01 % mit einer Messunsicherheit von 0,01 % geeignet. Verfahren E ist für die Bestimmung des Wassergehalts bis hinab zu 0,001 % mit einer Messunsicherheit von 0,001 % geeignet. Die angegebenen Messunsicherheiten sind Nachweisgrenzen, die außerdem von der größten möglichen Probenmasse abhängen. Der Wassergehalt wird als Massenanteil an Wasser in Prozent ausgedrückt.
Verfahren D ist geeignet für Polyamid (PA), Polycarbonat (PC), Polypropylen (PP), Polyethylen (PE), Epoxidharz, Polyethylenterephthalat (PET), Polyester, Polytetrafluorethylen (PTFE), Polyvinylchlorid (PVC), Polylactid (PLA), Polyamidimid (PAI), wird jedoch insbesondere für Proben, die NH3 freisetzen können, nicht empfohlen. Die Verfahren A, B, C und E sind im Allgemeinen für alle Arten von Kunststoffen und für jeden Feuchtegehalt geeignet.
Der Wassergehalt ist ein wichtiger Parameter bei der Verarbeitung von Werkstoffen, und es wird erwartet, dass er stets unter dem in den entsprechenden Werkstoffnormen festgelegten Wert bleibt.
In diesem Dokument sind sechs alternative Verfahren festgelegt:
— Verfahren A ist ein Extraktionsverfahren mit wasserfreiem Methanol und anschließender Titration des extrahierten 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 z. B. auch 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 Trägergas in die Titrationszelle überführt, in der anschließend entweder die Titration des gesammelten Wassers nach dem Karl-Fischer-Verfahren oder eine coulometrische Bestimmung des gesammelten Wassers mit Hilfe eines Feuchtesensors erfolgt. Es kann auf alle Kunststoffe angewendet werden und ist auf Granulate mit einer Korngröße kleiner als 4 mm × 4 mm × 3 mm anwendbar.
Plastiques - Dosage de l'eau (ISO 15512:2019)
Le présent document 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 Méthode D est applicable au dosage de l'eau à des niveaux aussi faibles que 0,01 % avec une précision de 0,01 %. La Méthode E est applicable au dosage de l'eau à des niveaux aussi faibles que 0,001 % avec une précision de 0,001 %. Les précisions indiquées sont les limites de détection qui dépendent également du poids maximal possible de l'échantillon. La teneur en eau est exprimée en pourcentage (fraction massique) d'eau.
La Méthode D convient pour le polyamide (PA), le polycarbonate (PC), le polypropylène (PP), le polyéthylène (PE), la résine époxyde, le poly(téréphtalate d'éthylène) (PET), le polyester, le polytétrafluoroéthylène (PTFE), le poly(chlorure de vinyle) (PVC), l'acide polylactique (PLA), le polyamide-imide (PAI). Elle est en particulier déconseillée pour les échantillons pouvant libérer du NH3. Les méthodes A, B, C et E convient généralement pour tout type de plastique et tout degré d'humidité.
La teneur en eau est un paramètre important de la mise en œuvre des matériaux et elle doit rester en dessous du niveau spécifié dans la norme de produit appropriée.
1.1 Six méthodes possibles sont spécifiées dans le présent document.
— 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. Cette méthode peut également être utilisée, par exemple, pour les poudres de prépolymères 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 ou un dosage coulométrique au moyen d'un capteur d'humidité. 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 une fiole à échantillon chauffée. 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 faut effectuer périodiquement des vérifications de la présence de grandes quantités de composés volatils, par exemple par chromatographie en
Polimerni materiali - Določevanje vode (ISO 15512:2019)
V tem dokumentu je določenih šest alternativnih metod.
– 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 ali kulometrično določanje s senzorjem vlage. Uporabiti jo je mogoče za vse polimerne elemente in velja za granule, manjše od 4 mm × 4 mm × 3 mm.
– Metoda B2 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.
– Metoda D je termokulometrična metoda z uporabo celice difosforjevega pentoksida (P2O5) za odkrivanje izparjene vode. Voda v preskusni količini izpari in se prenese v celico senzorja prek nosilnega plina (suh zrak ali dušik), čemur sledi kulometrično določanje zbrane vode. 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.
To je posebej povezano s hlapnimi komponentami, ki lahko reagirajo s kislim premazom senzorja difosforjevega pentoksida, npr. z amoniakom ali katero koli vrsto aminov. Redno je treba preverjati prisotnost velikih količin hlapnih spojin. Tako preverjanje je zlasti potrebno za nove tipe ali razrede materiala.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2019
Nadomešča:
SIST EN ISO 15512:2017
Polimerni materiali - Določevanje vode (ISO 15512:2019)
Plastics - Determination of water content (ISO 15512:2019)
Kunststoffe - Bestimmung des Wassergehaltes (ISO 15512:2019)
Plastiques - Dosage de l'eau (ISO 15512:2019)
Ta slovenski standard je istoveten z: EN ISO 15512:2019
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 15512
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2019
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 15512:2016
English Version
Plastics - Determination of water content (ISO
15512:2019)
Plastiques - Dosage de l'eau (ISO 15512:2019) Kunststoffe - Bestimmung des Wassergehaltes (ISO
15512:2019)
This European Standard was approved by CEN on 4 May 2019.
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, Serbia, 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: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15512:2019 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 15512:2019) 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 November 2019, and conflicting national standards
shall be withdrawn at the latest by November 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 15512:2016.
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, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 15512:2019 has been approved by CEN as EN ISO 15512:2019 without any modification.
INTERNATIONAL ISO
STANDARD 15512
Fifth edition
2019-05
Plastics — Determination of water
content
Plastiques — Dosage de l'eau
Reference number
ISO 15512:2019(E)
©
ISO 2019
ISO 15512:2019(E)
© ISO 2019
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
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Published in Switzerland
ii © ISO 2019 – All rights reserved
ISO 15512:2019(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Method A — Extraction with anhydrous methanol . 2
4.1 Principle . 2
4.2 Reagents. 2
4.3 Apparatus . 2
4.4 Preparation of test sample . 3
4.4.1 Granules or powder . 3
4.4.2 Finished articles . 3
4.5 Procedure . 3
4.5.1 Precautions . 3
4.5.2 Preparation of test portions . 3
4.5.3 Determination . 3
4.6 Expression of results . 4
4.7 Precision . 4
5 Method B1 — Water vaporization using a heating tube oven . 4
5.1 Principle . 4
5.2 Reagents. 4
5.3 Apparatus . 5
5.4 Preparation of test sample . 7
5.5 Procedure . 7
5.5.1 Precautions . 7
5.5.2 Preparation of apparatus . 7
5.5.3 Equipment checks . 7
5.5.4 Determination . 8
5.6 Expression of results . 8
5.7 Precision . 9
6 Method B2 — Water vaporization using a heated sample vial . 9
6.1 Principle . 9
6.2 Reagents. 9
6.3 Apparatus .10
6.4 Preparation of test sample .11
6.5 Procedure .12
6.5.1 Preparation of apparatus .12
6.5.2 Equipment check .12
6.5.3 Determination .12
6.6 Expression of results .14
6.7 Precision .14
7 Method C — Manometric method .15
7.1 Principle .15
7.2 Reagents.15
7.3 Apparatus .15
7.4 Preparation of test sample .16
7.5 Procedure .16
7.5.1 Equipment .16
7.5.2 Outgassing .17
7.5.3 Calibration .17
7.5.4 Determination .19
7.6 Expression of results .20
ISO 15512:2019(E)
7.7 Precision .20
8 Method D — Water detection by using a diphosphorus pentoxide cell .20
8.1 Principle .20
8.2 Reagents.21
8.3 Apparatus .21
8.4 Preparation of test sample .22
8.5 Procedure .23
8.5.1 Preparation of apparatus .23
8.5.2 Rinsing the system .23
8.5.3 Tare measurement .23
8.5.4 Cell factor.23
8.5.5 Equipment check .23
8.5.6 Determination .24
8.6 Expression of results .24
8.7 Precision .25
9 Method E — Determination of water content by calcium hydride method .25
9.1 Principle .25
9.2 Reagents.26
9.3 Apparatus .26
9.4 Preparation of test sample .27
9.5 Procedure .27
9.5.1 Equipment check .27
9.5.2 Calibration .28
9.5.3 Determination .28
9.5.4 Expression of results .29
9.6 Precision .29
10 Test report .29
Annex A (informative) Alternative sample preparation methods and titration methods .30
Annex B (informative) Selection of the optimum heating temperature and heating time for
the water content determination .31
Annex C (normative) Determination of the water content of a water standard .33
Bibliography .34
iv © ISO 2019 – All rights reserved
ISO 15512:2019(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 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 61, Plastics, Subcommittee SC 5, Physical-
chemical properties.
This fifth edition cancels and replaces the fourth edition (ISO 15512:2016), which has been technically
revised. The main change compared to the previous edition is as follows:
— addition of two alternative methods for water determination (Methods D and E).
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.
ISO 15512:2019(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 should, 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 document is intended to be followed
strictly.
The temperature settings for the vaporization method are not specified in this document. 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 needs to be optimized depending on 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 document, 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.
vi © ISO 2019 – All rights reserved
INTERNATIONAL STANDARD ISO 15512:2019(E)
Plastics — Determination of water content
1 Scope
This document 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 %. Method D is suitable for the determination of water content as low as 0,01 % with an
accuracy of 0,01 %. Method E is suitable for the determination of water content as low as 0,001 % with
an accuracy of 0,001 %. The stated accuracies are detection limits which depend also on the maximal
possible sample mass. The water content is expressed as a percentage mass fraction of water.
Method D is suitable for polyamide (PA), polycarbonate (PC), polypropylene (PP), polyethylene (PE), epoxy
resin, polyethylene terephthalate (PET), polyester, polytetrafluoroethylene (PTFE), polyvinyl chloride
(PVC), polylactide (PLA), polyamidimid (PAI), it is especially not recommended for samples which can
release NH . Methods A, B, C and E are generally suitable for all types of plastic and moisture level.
Water content is an important parameter for processing materials and is expected to remain below the
level specified in the appropriate material standard.
Six alternative methods are specified in this document.
— 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 or a coulometric determination by means of a moisture sensor 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.
— Method D is a thermocoulometric method using a diphosphorus pentoxide (P O ) cell for the
2 5
detection of the vaporized water. The water contained in the test portion is vaporized and carried
to the sensor cell by a dry air or nitrogen carrier gas, followed by a coulometric determination of
the collected water. 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.
This is specially related to volatile components which can react with the acidic coating of the
diphosphorus pentoxide sensor, e.g. ammonia or any kind of amines. Checks for the presence of
large amounts of volatile compounds are to be carried out periodically. Such checks are particularly
required for new types or grades of material.
ISO 15512:2019(E)
— Method E is a calcium hydride based method. The water content of a sample evaporates due to a
combination of vacuum and heating. The evaporated water reacts with calcium hydride to molecular
hydrogen and calcium hydroxide. The hydrogen causes an increase of pressure in the vacuum that is
proportional to the evaporated water. Volatile components, that do not react with calcium hydride
condensate in a cooling trap and do not affect the measurement.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 760, Determination of water — Karl Fischer method (General method)
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Method A — Extraction with anhydrous methanol
4.1 Principle
A test portion is extracted with anhydrous methanol and the extracted water determined by titration
using the Karl Fischer method.
4.2 Reagents
During the analysis, use only reagents of recognized analytical grade.
4.2.1 Titration medium, methanol anhydrous, having a water content less than 0,1 % mass fraction.
Other solvents can be used if shown to be comparable.
4.2.2 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.
4.3 Apparatus
Ordinary laboratory apparatus and the following.
4.3.1 Glass flasks, approximately 250 ml capacity, provided with a suitable cap preventing moisture
uptake or release.
4.3.2 Conical titration flasks, approximately 150 ml capacity, with standard ground necks and
provided with ground-glass stoppers.
4.3.3 Reflux condensers, with ground neck capable of being fitted on to the flasks (4.3.2) and on to
the tubes (4.3.4).
2 © ISO 2019 – All rights reserved
ISO 15512:2019(E)
4.3.4 Water-absorption tubes with ground joints, containing calcium chloride or any other suitable
drying agent.
4.3.5 Heaters, suitable for the conical titration flasks (4.3.2).
4.3.6 Desiccator, containing a suitable desiccant.
4.3.7 Analytical balance, accurate to 0,2 mg.
4.3.8 Karl Fischer apparatus, for determining water content in accordance with ISO 760.
4.4 Preparation of test sample
4.4.1 Granules or powder
Take a representative sample of approximately 100 g. Put the sample into a pre-dried glass flask (4.3.1)
and immediately close it with a stopper.
It is desirable to pre-dry the container in an oven and then cool it over a suitable desiccant.
4.4.2 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.
4.5 Procedure
4.5.1 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.
4.5.2 Preparation of test portions
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.
4.5.3 Determination
Carefully dry the apparatus.
Weigh each test portion to the nearest 1 mg into a conical titration flask (4.3.2) fitted with a ground-
glass stopper. Pipette 50 ml of anhydrous methanol (4.2.1) 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 (4.3.6) pending continuation of the test.
Unstopper the flasks and quickly attach them to reflux condensers (4.3.3) fitted with calcium chloride
tubes (4.3.4). 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.
ISO 15512:2019(E)
Use the Karl Fischer apparatus (4.3.8) to titrate the contents of each flask with Karl Fischer reagent
(4.2.2).
NOTE Alternative sample preparation methods and titration methods are given in Annex A.
4.6 Expression of results
The water content, w, expressed as a percentage mass fraction, for each of the two determinations is
given by Formula (1):
VV− ·T
()
w = ·100 (1)
m
where
V is the volume, expressed in millilitres, of Karl Fischer reagent used for the determination;
V is the volume, expressed in millilitres, of Karl Fischer reagent used for the blank test;
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
V − V . In this case, the numerator in Formula (1) simplifies to V × T.
1 2
4.7 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.
5 Method B1 — Water vaporization using a heating tube oven
5.1 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 → 2 HI + SO
2 2 2 3
Unlike the conventional Karl Fischer reagents that include iodine, the coulometric technique generates
the iodine electrolytically from iodide:
−−
22II→+ e
with 10,71 C of generating current corresponding to 1 mg of water in accordance with Faraday’s Law.
5.2 Reagents
During the analysis, use only reagents of recognized analytical grade.
4 © ISO 2019 – All rights reserved
ISO 15512:2019(E)
5.2.1 Anode solution, containing iodide ions to generate iodine in the reaction mixture, in accordance
with the equipment manufacturer's instructions.
5.2.2 Cathode solution, containing a suitable salt in methanol (or another suitable organic solvent),
prepared in accordance with the equipment manufacturer’s instructions.
5.2.3 Universal single anode reagent, containing iodide ions to generate iodine in the reaction
mixture, in accordance with the equipment manufacturer's instructions, for use in a diaphragm-free cell.
NOTE A universal single anode coulometric reagent is applied in diaphragm-free titration cells. Titration
cells with diaphragm require the use of a separate anode and cathode solution.
5.2.4 Neutralization solution, consisting of approximately 4 mg/ml of water in propylene carbonate,
ethylene glycol monomethyl ether (2-methoxyethanol), or methyl cellosolve.
5.2.5 Nitrogen gas (N ), containing less than 5 μg/g of water.
5.3 Apparatus
Ordinary laboratory apparatus and the following.
5.3.1 Coulometric Karl Fischer titrator, consisting of a control unit and a titration-cell assembly
equipped with a generator cell, with or without diaphragm, dual platinum sensing electrodes, and a
magnetic stirrer (see Figure 1).
The instrument is designed to coulometrically generate iodine that reacts stoichiometrically with the
water present in the cell. The coulombs of electricity required to generate the reagent are converted to
micrograms of water and is given as a direct digital readout.
NOTE A diaphragm-free cell is accurate enough for many applications. However, some applications can
require a diaphragm for the best possible accuracy. This can be checked with the equipment supplier.
5.3.2 Water vaporizer, consisting of an oven capable of heating the sample to at least 300 °C, a heating
tube (see Figure 2), a temperature control unit, a carrier-gas flow meter, and carrier-gas drying tubes
containing desiccant.
5.3.3 Microsyringe, with capacity of 10 μl, calibrated.
5.3.4 Sample boat.
Aluminium foil can be used to hand-fashion a disposable boat large enough to contain the sample and
small enough to fit into the heating tube.
5.3.5 Suitable desiccant, for the carrier-gas drying tubes (5.3.2).
5.3.6 Molecular sieve, pore size 0,3 nm, desiccant for carrier gas.
5.3.7 PTFE sleeves, to be used to maintain the air-tightness of the ground glass joints of the system.
Alternatively, grease, containing little or no water and having low water absorptivity, can be used.
ISO 15512:2019(E)
Key
1 coulometric Karl Fischer meter 7 oven
2 exhaust gas 8 heating tube
3 titration cell 9 water-absorption tubes (filled with desiccant, for example P O )
2 5
4 titration controller 10 flow meter
5 power supply 11 temperature controller
6 water vaporizer 12 N gas
Figure 1 — Flowchart of a system used for the determination of water content using method B1
a) Push-bar type
b) Magnet type
Key
1 sample boat 3 sample-boat inlet
2 sample inlet 4 magnet
Figure 2 — Heating tubes
6 © ISO 2019 – All rights reserved
ISO 15512:2019(E)
5.4 Preparation of test sample
The test material can be in any form, such as granules, moulding powder, fabricated shapes, or
moulded items.
Cut fabricated shapes and moulded items to a suitable size. Granules shall be smaller than
4 mm × 4 mm × 3 mm.
Take a representative sample of ≤10 g. Due to the small size of the sample, care shall be taken to ensure
that it is in fact representative.
5.5 Procedure
5.5.1 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.
5.5.2 Preparation of apparatus
Refer to Figure 1 for the following procedure.
Assemble the water vaporizer (5.3.2) and coulometric Karl Fischer titrator (5.3.1) as directed in the
manufacturer’s instructions. Fill the absorption tubes with desiccating agent (5.3.2) as directed in the
manufacturer’s instructions.
Pour approximately 200 ml (adjust for the container size) of the anode solution (5.2.1) into the generator
cell and approximately 10 ml of the cathode solution (5.2.2) into the cathode solution cell (5.3.1) (adjust
these amounts for the container size). The surface of the cathode solution shall be below the level of the
anode solution to prevent backflow contamination of the cathode solution.
NOTE A universal single anode coulometric reagent is applied in diaphragm-free titration cells. Titration
cells with diaphragm require the use of a separate anode and cathode solution.
Start the titration cell. If the cell potential shows a negative value, indicating that the anode solution
contains an excess of iodine, add 50 μl to 200 μl (adjust for the container size) of the neutralization
solution (5.2.4).
Disconnect the tube connecting the vaporizer unit to the titration cell. Set the carrier gas flow to
200 ml/min to 300 ml/min and heat the oven to the desired temperature to remove any residual water
from the vaporizer (5.3.2).
Remove any residual water from the walls e.g. by gently swirling the cell. If possible, stir the solution for
1 min in the “TITRATION” mode to dry and stabilize the inner atmosphere.
Reconnect the tube from the vaporizer unit to the titration cell. Keep the carrier-gas flow on during the
whole titration. The instrument is then ready for sample analysis.
5.5.3 Equipment checks
To check if the coulometric Karl Fischer titrator is functioning properly, carry out a determination with
a known amount of water as follows. With the analyser stabilized and in the “READY” position, start
the titration process and carefully inject 5 µl of distilled water into the cell using a 10 µl syringe (5.3.3).
When the titration process is finished, record the reading. This reading should be (5 000 ± 250) µg.
To check if the whole system is functioning properly, carry out a determination with any available
certified water standard for Karl Fischer ovens. Examples are:
— sodium tartrate dihydrate with 15,6 % ± 0,5 % water content;
ISO 15512:2019(E)
— potassium tartrate hemihydrate with 3,8 % ± 0,2 % water content;
— sodium tungstate diluted for 1,00 % ± 0,03 %.
5.5.4 Determination
Heat the oven to the desired temperature and place the sample boat (5.3.4) in the heating tube and push
it into the oven to dry and also to back purge any residual water contained in the sample-boat inlet.
For the heating temperature, refer to the material standard. As the heating temperature is also
dependent on equipment used and the practical circumstances, the heating temperature needs to be
optimized using the method described in Annex B. If the heating temperature is not mentioned in the
material standard or if there is no material standard, then use the method mentioned in Annex B to
determine the optimum heating temperature.
After a few minutes, move the sample boat to the sample inlet port and allow it to cool.
Weigh a test portion of the sample (5.4) directly into the sample boat (which shall be removed from
the heating tube for this purpose) or on to a piece of aluminium foil (see next paragraph). Appropriate
mass
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