Natural gas - Determination of water by the Karl Fischer method - Part 2: Volumetric procedure (ISO 10101-2:2022)

This document specifies a volumetric procedure for the determination of water content in natural gas. Volumes are expressed in cubic metres at a temperature of 273,15 K (0 °C) and a pressure of 101,325 kPa (1 atm). It applies to water concentrations between 5 mg/m3 and 5 000 mg/m3.

Erdgas - Bestimmung des Wassergehaltes nach Karl Fischer - Teil 2: Volumetrisches Verfahren (ISO 10101-2:2022)

Dieses Dokument legt ein volumetrisches Verfahren zur Bestimmung des Wassergehaltes von Erdgas fest. Die Volumina werden in Kubikmetern angegeben und beziehen sich auf eine Temperatur von 273,15 K (0 °C) und einen Druck von 101,325 kPa (1 atm). Dieses Verfahren gilt für Wasseranteile zwischen 5 mg/m3 und 5 000 mg/m3.
WARNUNG — Falls die Apparatur in einem explosionsgefährdeten Bereich aufgestellt wird, sollten die örtlichen Sicherheitsbestimmungen beachtet werden.

Gaz naturel - Dosage de l'eau par la méthode de Karl Fischer - Partie 2: Méthode volumétrique (ISO 10101-2:2022)

Zemeljski plin - Določevanje vode po Karl-Fischerjevi metodi - 2. del: Volumetrijska metoda (ISO 10101-2:2022)

General Information

Status
Published
Public Enquiry End Date
01-Feb-2021
Publication Date
14-Nov-2022
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
26-Oct-2022
Due Date
31-Dec-2022
Completion Date
15-Nov-2022

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SLOVENSKI STANDARD
SIST EN ISO 10101-2:2022
01-december-2022
Nadomešča:
SIST EN ISO 10101-2:2000

Zemeljski plin - Določevanje vode po Karl-Fischerjevi metodi - 2. del: Volumetrijska

metoda (ISO 10101-2:2022)

Natural gas - Determination of water by the Karl Fischer method - Part 2: Volumetric

procedure (ISO 10101-2:2022)

Erdgas - Bestimmung des Wassergehaltes nach Karl Fischer - Teil 2: Volumetrisches

Verfahren (ISO 10101-2:2022)
Gaz naturel - Dosage de l'eau par la méthode de Karl Fischer - Partie 2: Méthode
volumétrique (ISO 10101-2:2022)
Ta slovenski standard je istoveten z: EN ISO 10101-2:2022
ICS:
75.060 Zemeljski plin Natural gas
SIST EN ISO 10101-2:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 10101-2:2022
---------------------- Page: 2 ----------------------
SIST EN ISO 10101-2:2022
EN ISO 10101-2
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2022
EUROPÄISCHE NORM
ICS 75.060 Supersedes EN ISO 10101-2:1998
English Version
Natural gas - Determination of water by the Karl Fischer
method - Part 2: Volumetric procedure (ISO 10101-
2:2022)

Gaz naturel - Dosage de l'eau par la méthode de Karl Erdgas - Bestimmung des Wassergehaltes nach Karl

Fischer - Partie 2: Méthode volumétrique (ISO 10101- Fischer - Teil 2: Volumetrisches Verfahren (ISO 10101-

2:2022) 2:2022)
This European Standard was approved by CEN on 26 August 2022.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye 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

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10101-2:2022 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 10101-2:2022
EN ISO 10101-2:2022 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 10101-2:2022
EN ISO 10101-2:2022 (E)
European foreword

This document (EN ISO 10101-2:2022) has been prepared by Technical Committee ISO/TC 193

"Natural gas" in collaboration with Technical Committee CEN/TC 238 “Test gases, test pressures,

appliance categories and gas appliance types” 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 March 2023, and conflicting national standards shall

be withdrawn at the latest by March 2023.

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 10101-2:1998.

Any feedback and questions on this document should be directed to the users’ national standards

body/national committee. A complete listing of these bodies can be found on the CEN website.

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, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the

United Kingdom.
Endorsement notice

The text of ISO 10101-2:2022 has been approved by CEN as EN ISO 10101-2:2022 without any

modification.
---------------------- Page: 5 ----------------------
SIST EN ISO 10101-2:2022
---------------------- Page: 6 ----------------------
SIST EN ISO 10101-2:2022
INTERNATIONAL ISO
STANDARD 10101-2
Second edition
2022-08
Natural gas — Determination of water
by the Karl Fischer method —
Part 2:
Volumetric procedure
Gaz naturel — Dosage de l'eau par la méthode de Karl Fischer —
Partie 2: Méthode volumétrique
Reference number
ISO 10101-2:2022(E)
© ISO 2022
---------------------- Page: 7 ----------------------
SIST EN ISO 10101-2:2022
ISO 10101-2:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

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 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 the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 10101-2:2022
ISO 10101-2:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Reagents ........................................................................................................................................................................................................................ 2

6 Apparatus .................................................................................................................................................................................................................... 3

7 Determination of the water equivalent of the Karl Fischer reagent ............................................................3

8 Sampling ....................................................................................................................................................................................................................... 4

9 Procedure ....................................................................................................................................................................................................................4

10 Expression of results ....................................................................................................................................................................................... 6

10.1 Method of calculation ....................................................................................................................................................................... 6

10.2 Measurement uncertainty ............................................................................................................................................................ 6

11 Test report .................................................................................................................................................................................................................. 6

Annex A (informative) Karl Fischer apparatus ........................................................................................................................................ 8

Bibliography .............................................................................................................................................................................................................................11

iii
© ISO 2022 – All rights reserved
---------------------- Page: 9 ----------------------
SIST EN ISO 10101-2:2022
ISO 10101-2:2022(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 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 the following

URL: www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 193, Natural Gas, Subcommittee SC 1,

Analysis of natural gas, in collaboration with the European Committee for Standardization (CEN)

Technical Committee CEN/TC 238, Test gases, test pressures, appliance categories and gas appliance types,

in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 10101-2:1993), which has been technically

revised.
The main changes are as follows:
— Clause 2 and Bibliography were revised;
— New fixed structure numbering inserted;
— Clause 5 was modified;
— Clause 9 was modified;
— 10.2 was modified.
A list of all parts in the ISO 10101 series can be found on the ISO website.
© ISO 2022 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 10101-2:2022
ISO 10101-2:2022(E)
Introduction

Water vapour may be present in natural gas due to, for example, natural occurrence in the well

production stream, the storage of gas in underground reservoirs, transmission or distribution through

mains containing moisture or other reasons.
© ISO 2022 – All rights reserved
---------------------- Page: 11 ----------------------
SIST EN ISO 10101-2:2022
---------------------- Page: 12 ----------------------
SIST EN ISO 10101-2:2022
INTERNATIONAL STANDARD ISO 10101-2:2022(E)
Natural gas — Determination of water by the Karl Fischer
method —
Part 2:
Volumetric procedure

WARNING — Local safety regulations should be taken into account, when the equipment is located in

hazardous areas.
1 Scope

This document specifies a volumetric procedure for the determination of water content in natural gas.

Volumes are expressed in cubic metres at a temperature of 273,15 K (0 °C) and a pressure of 101,325 kPa

3 3
(1 atm). It applies to water concentrations between 5 mg/m and 5 000 mg/m .
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 383, Laboratory glassware — Interchangeable conical ground joints

ISO 10101-1, Natural gas- Determination of water by the Karl Fischer method – Part 1- Introduction

ISO 14532, Natural gas — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 14532 apply.

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 https:// www .electropedia .org/
4 Principle

A measured volume of gas is passed through a cell containing a relatively small volume of absorbent

solution. Water in the gas is extracted by the absorbent solution and subsequently titrated with

Karl Fischer reagent. The design of the cell and the absorbent solution are chosen to ensure efficient

collection of the water at the high flowrates necessary.

The principle and chemical reactions of the Karl Fischer method are given in ISO 10101-1:2020, Clauses 4

and 5; interferences are also described in ISO 10101-1:2020, Clause 5.

ISO 10101-1:2020, Clause 5 describes interfering substances which may be present in natural gas and

corrections for the interference of hydrogen sulfide and mercaptans.
© ISO 2022 – All rights reserved
---------------------- Page: 13 ----------------------
SIST EN ISO 10101-2:2022
ISO 10101-2:2022(E)
5 Reagents

5.1 Karl Fischer reagent, of which the water equivalent is approximately 5 mg/ml.

NOTE For most applications, commercially available Karl Fischer (KF) reagent with a water equivalent of

approximately 5 mg/ml has been found adequate.

The reagent can be bought as a one-component reagent, which contains all the necessary reagents

(iodine, sulfur dioxide and the base (e.g. imidazole)) dissolved in an anhydrous solvent (methanol or

2-methoxyethanol) or it can be provided as two-component reagent, i.e. a solvent reagent and a titrant

reagent which are mixed before use.

The solvent reagent contains sulfur dioxide and a base (e.g. an alkali or alkaline earth metal benzoate,

ammonia, imidazole). The titrant reagent contains iodine. The two-component reagent provides a stable

titre as long as any moisture is prevented from entering into the reagents and a better shelf life.

If required, it may be prepared following the procedure in 5.1.1.
5.1.1 Preparation of Karl Fischer reagent
5.1.1.1 Components

5.1.1.1.1 Methanol, with a water content of less than 0,01 % (mass fraction). Use commercially

available dry methanol, anhydrificated in the lab by one of the following procedures

5.1.1.1.1.1 Place 2 l of methanol in a two-neck 3 l flask and add 10 g of magnesium turnings. Add a

crystal of iodine, connect the flask to a reflux condenser and leave overnight. Next day, add a further

5 g of magnesium turnings and reflux for 1 h. Connect the top of the reflux condenser to a still head,

a double surface condenser and a collection flask. Disconnect the water flow through the condenser

originally used for reflux and distil the contents of the fl
...

SLOVENSKI STANDARD
oSIST prEN ISO 10101-2:2021
01-januar-2021

Zemeljski plin - Določevanje vode po Karl-Fischerjevi metodi - 2. del: Volumetrijski

postopek (ISO/DIS 10101-2:2020)

Natural gas - Determination of water by the Karl Fischer method - Part 2: Volumetric

procedure (ISO/DIS 10101-2:2020)

Erdgas - Bestimmung des Wassergehaltes nach Karl Fischer - Teil 2: Volumetrisches

Verfahren (ISO/DIS 10101-2:2020)
Gaz naturel - Dosage de l'eau par la méthode de Karl Fischer - Partie 2: Méthode
volumétrique (ISO/DIS 10101-2:2020)
Ta slovenski standard je istoveten z: prEN ISO 10101-2
ICS:
75.060 Zemeljski plin Natural gas
oSIST prEN ISO 10101-2:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 10101-2:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 10101-2:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 10101-2
ISO/TC 193/SC 1 Secretariat: NEN
Voting begins on: Voting terminates on:
2020-11-13 2021-02-05
Natural gas — Determination of water by the Karl Fischer
method —
Part 2:
Volumetric procedure
ICS: 75.060
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 10101-2:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 10101-2:2021
ISO/DIS 10101-2:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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

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 the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 10101-2:2021
ISO/DIS 10101-2:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Reagents ........................................................................................................................................................................................................................ 2

5.1 Karl Fischer reagent- of which the water equivalent is approximately 5 mg/ml. ......................... 2

5.1.1 Preparation of KF reagent ........................................................................................................................................ 2

5.2 Absorbent solution. ............................................................................................................................................................................. 3

5.2.1 Components ......................................................................................................................................................................... 3

5.2.2 Preparation of the absorbent solution .......................................................................................................... 3

6 Apparatus ..................................................................................................................................................................................................................... 3

7 Standardization of the Karl Fischer reagent ........................................................................................................................... 3

8 Sampling ........................................................................................................................................................................................................................ 4

9 Procedure..................................................................................................................................................................................................................... 4

10 Expression of results ........................................................................................................................................................................................ 6

10.1 Method of calculation ........................................................................................................................................................................ 6

10.2 Precision ....................................................................................................................................................................................................... 6

11 Test report ................................................................................................................................................................................................................... 6

Annex A (informative) Karl Fischer apparatus .......................................................................................................................................... 7

Bibliography .............................................................................................................................................................................................................................11

© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 10101-2:2021
ISO/DIS 10101-2:2020(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 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 the following

URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 193, Natural Gas, Subcommittee SC 1,

Analysis of Natural Gas.

ISO 10101 consists of the following parts, under the general title Natural gas — Determination of water

by the Karl Fischer method:
— Part 1: Introduction
— Part 2: Volumetric procedure
— Part 3: Coulometric procedure
Annex A forms an integral part of this part of ISO 10101.
A list of all parts in the ISO 10101 series can be found on the ISO website.
iv © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 10101-2:2021
ISO/DIS 10101-2:2020(E)
Introduction

Water vapour may be present in natural gas due to, for example, natural occurrence in the well

production stream, the storage of gas in underground reservoirs, transmission or distribution through

mains containing moisture or other reasons.

WARNING — Local safety regulations must be taken into account, when the equipment is located

in hazardous areas.
© ISO 2020 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 10101-2:2021
---------------------- Page: 8 ----------------------
oSIST prEN ISO 10101-2:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 10101-2:2020(E)
Natural gas — Determination of water by the Karl Fischer
method —
Part 2:
Volumetric procedure
1 Scope

This document specifies a volumetric procedure for the determination of water content in natural gas.

Volumes are expressed in cubic metres at a temperature of 273,15 K (0 °C) and a pressure of 101,325

3 3
kPa (1 atm). It applies to water concentrations between 5 mg/m and 5 000 mg/m .
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 383:1976, Laboratory glassware — Interchangeable conical ground joints

ISO 10101-1:2020, Natural gas- Determination of water by the Karl Fischer method – Part 1- Introduction

ISO 14532, Natural gas — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 14532 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
4 Principle

A measured volume of gas is passed through a cell containing a relatively small volume of absorbent

solution. Water in the gas is extracted by the absorbent solution and subsequently titrated with

Karl Fischer reagent. The design of the cell and the absorbent solution are chosen to ensure efficient

collection of the water at the high flowrates necessary.

The principle and chemical reactions of the Karl Fischer method are given in ISO 10101-1:2020, clauses

4 and 5; interferences are also described in clause 5 of ISO 10101-1:2020.

Clause 5 of ISO 10101-1:2020 describes interfering substances which may be present in natural gas and

corrections for the interference of hydrogen sulfide and mercaptans.
© ISO 2020 – All rights reserved 1
---------------------- Page: 9 ----------------------
oSIST prEN ISO 10101-2:2021
ISO/DIS 10101-2:2020(E)
5 Reagents

5.1 Karl Fischer reagent- of which the water equivalent is approximately 5 mg/ml.

NOTE For most applications, commercially available Karl Fischer reagent with a water equivalent of

approximately 5 mg/ml has been found adequate.

The reagent can be bought as a one-component reagent, which contains all the necessary reagents

(iodine, sulfur dioxide and the base (e.g. imidazole)) dissolved in an anhydrous solvent (methanol or

2-methoxyethanol) or it can be provided as two-component reagent, i.e. a solvent reagent and a titrant

reagent which are mixed before use.

The solvent reagent contains sulfur dioxide and a base (e.g. an alkali or alkaline earth metal benzoate,

ammonia, imidazole). The titrant reagent contains iodine. The two-component reagent provides a stable

titre as long as any moisture is prevented from entering into the reagents and a better shelf life.

If required, it may be prepared following the procedure in 5.1.1.
5.1.1 Preparation of KF reagent
5.1.1.1 Components

5.1.1.1.1 Methanol, with a water content of less than 0,01 % (m/m). Use commercially available

dry methanol, anhydrificated in the lab by one of the following procedures

5.1.1.1.1.1 Place 2 litres of methanol in a two-neck 3 litres flask and add 10 g of magnesium turnings.

Add a crystal of iodine, connect the flask to a reflux condenser and leave overnight. Next day, add a

further 5 g of magnesium turnings and reflux for 1 h. Connect the top of the reflux condenser to a still

head, a double surface condenser and a collection flask. Disconnect the water flow through the condenser

originally used for reflux and distil the contents of the flask. Discard the first 150 ml of condensate. Distil

the rest into dried 1 litre flasks. Vent the system through a drying tube during distillation.

5.1.1.1.1.2 Dry the methanol over a freshly activated molecular sieve.
5.1.1.1.2 2-Methoxyethanol, with a water content of less than 0,01 % (m/m).

NOTE This can be used as an alternative to methanol (5.1.1.1.1) with a lower vapour pressure and therefore

less losses due to evaporation during sampling of the gas
5.1.1.1.3 Imidazol, anhydrous
5.1.1.1.4 Sulfur dioxide, liquefied and dry
5.1.1.1.5 Iodine
5.1.1.2 Preparation
Measure 300 ml of dry methanol (5.1.1.1.1) or 2-methoxy
...

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