EN ISO 10304-4:2022

SLOVENSKI STANDARD
01-julij-2022
Nadomešča:
SIST EN ISO 10304-4:2000
Kakovost vode - Določevanje raztopljenih anionov z ionsko tekočinsko
kromatografijo - 4. del: Določevanje klorata, klorida in klorita v malo onesnaženih
vodah (ISO 10304-4:2022)
Water quality - Determination of dissolved anions by liquid chromatography of ions - Part
4: Determination of chlorate, chloride and chlorite in water with low contamination (ISO
10304-4:2022)
Wasserbeschaffenheit - Bestimmung von gelösten Anionen mittels
Ionenchromatographie - Teil 4: Bestimmung von Chlorat, Chlorid und Chlorit in gering
belastetem Wasser (ISO 10304-4:2022)
Qualité de l'eau - Dosage des anions dissous par chromatographie des ions en phase
liquide - Partie 4: Dosage des ions chlorate, chlorure et chlorite dans des eaux
faiblement contaminées (ISO 10304-4:2022)
Ta slovenski standard je istoveten z: EN ISO 10304-4:2022
ICS:
13.060.50 Preiskava vode na kemične Examination of water for
snovi chemical substances
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 10304-4
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2022
EUROPÄISCHE NORM
ICS 13.060.50 Supersedes EN ISO 10304-4:1999
English Version
Water quality - Determination of dissolved anions by
liquid chromatography of ions - Part 4: Determination of
chlorate, chloride and chlorite in water with low
contamination (ISO 10304-4:2022)
Qualité de l'eau - Dosage des anions dissous par Wasserbeschaffenheit - Bestimmung von gelösten
chromatographie des ions en phase liquide - Partie 4: Anionen mittels Ionenchromatographie - Teil 4:
Dosage des ions chlorate, chlorure et chlorite dans des Bestimmung von Chlorat, Chlorid und Chlorit in gering
eaux faiblement contaminées (ISO 10304-4:2022) belastetem Wasser (ISO 10304-4:2022)
This European Standard was approved by CEN on 8 January 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, 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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10304-4:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 10304-4:2022) has been prepared by Technical Committee ISO/TC 147 "Water
quality" in collaboration with Technical Committee CEN/TC 230 “Water analysis” the secretariat of
which is held by DIN.
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 September 2022, and conflicting national standards
shall be withdrawn at the latest by September 2022.
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 10304-4:1999.
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 10304-4:2022 has been approved by CEN as EN ISO 10304-4:2022 without any
modification.
INTERNATIONAL ISO
STANDARD 10304-4
Second edition
2022-03
Water quality — Determination
of dissolved anions by liquid
chromatography of ions —
Part 4:
Determination of chlorate, chloride
and chlorite in water with low
contamination
Qualité de l'eau — Dosage des anions dissous par chromatographie
des ions en phase liquide —
Partie 4: Dosage des ions chlorate, chlorure et chlorite dans des eaux
faiblement contaminées
Reference number
ISO 10304-4:2022(E)
ISO 10304-4:2022(E)
© 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
ii
ISO 10304-4:2022(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Interferences . 2
5 Principle . 2
6 Reagents . 3
7 Apparatus . 6
8 Quality requirements for the separator column . 6
9 Sampling and sample pre-treatment .8
9.1 General requirements . 8
9.2 Sample pre-treatment in the case of elevated levels of chloride and bromide . 9
10 Procedure .9
10.1 General . 9
10.2 Calibration . 9
10.3 Measurement of samples using the standard calibration procedure . 10
10.4 Validity check of the calibration function . 10
11 Calculation .10
12 Expression of results .10
13 Test report .10
Annex A (informative) Performance data .12
Bibliography .15
iii
ISO 10304-4:2022(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 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 147, Water quality, Subcommittee
SC 2, Physical, chemical and biochemical methods, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 230, Water analysis, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 10304-4:1997), which has been
technically revised. The main changes compared to the previous edition are as follows:
— in the introduction, all requirements concerning the application of the method have been deleted
and moved to other clauses;
— in Clause 2, all the references made but withdrawn since the publication of the 1997 edition (e.g.
ISO 10304-2) have been deleted and the references ISO 5667-1 and ISO 5667-3 have been moved to
the Bibliography;
— in 6.8, various eluent formulations have been reduced to one example;
— in Clause 8, the calculation procedure for the peak resolution according to the USP definition
[Formula (1)] has been completed with the EP definition [Formula (2)] (both calculations are
equivalent);
— in 9.1, information that drinking water disinfection treatment using chlorine dioxide can cause the
formation of chlorite and chlorate (paragraph 2) and helpful precautions to minimize/eliminate
such formation (paragraph 3) have been added;
— in Clause 11, the option to report result concentrations in microgram per litre has been added.
A list of all parts in the ISO 10304 series can be found on the ISO website.
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.
iv
INTERNATIONAL STANDARD ISO 10304-4:2022(E)
Water quality — Determination of dissolved anions by
liquid chromatography of ions —
Part 4:
Determination of chlorate, chloride and chlorite in water
with low contamination
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices.
IMPORTANT — It is absolutely essential that tests conducted in accordance with this document
be carried out by suitably qualified staff.
1 Scope
This document specifies a method for the determination of the dissolved anions chlorate, chloride and
chlorite in water with low contamination (e.g. drinking water, raw water or swimming pool water).
The diversity of the appropriate and suitable assemblies and the procedural steps depending on them
permit a general description only.
For further information on the analytical technique, see Bibliography.
An appropriate pre-treatment of the sample (e.g. dilution) and the use of a conductivity detector (CD),
UV detector (UV) or amperometric detector (AD) make the working ranges given in Table 1 feasible.
Table 1 — Working ranges of the analytical method
Anion Working range Detection
a
mg/l
Chlorate 0,03 to 10 CD
Chloride 0,1 to 50 CD
0,05 to 1 CD
b
Chlorite 0,1 to 1 UV; λ = 207 nm to 220 nm
0,01 to 1 AD; 0,4 V to 1,0 V
a
The working range is restricted by the ion-exchange capacity of the columns. If necessary, samples can be adjusted to
this range by dilution.
b
The minimum working range for chlorite of 0,05 mg/l was obtained using calibration checks, but the interlaboratory
trials (see Table A.4) showed that it is difficult to obtain this with sufficient accuracy, and only if taking great care.
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 8466-1, Water quality — Calibration and evaluation of analytical methods — Part 1: Linear calibration
function
ISO 10304-4:2022(E)
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology 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 Interferences
Organic acids such as mono- and dicarboxylic acids or disinfection by-products (e.g. chloroacetic acid)
can interfere.
Dissolved organics can react with the working electrode of the amperometric detector, causing a
decrease in sensitivity.
The presence of fluoride, carbonate, nitrite and nitrate can cause interference with the determination
of chlorate, chloride and chlorite. The respective concentrations given in Table 2 are typical for
conductivity, UV and amperometric detectors.
Elevated loads of chloride and bromide can cause interference with the determination of chlorite and
chlorate. Remove chloride and bromide with the aid of special exchangers (9.2).
Solid particles and organic compounds (such as mineral oils, detergents and humic acids) shorten
the lifetime of the separator column. They are therefore eliminated from the sample prior to analysis
(Clause 9).
Table 2 — Typical cross-sensitivity of anions
a
Relation of the mass concentration of
Detection method
measured ion interfering ion
1 part chlorate 50 parts bromide CD
1 part chlorate 500 parts nitrate CD
1 part chloride 500 parts fluoride CD
1 part chloride 1 000 parts chlorite CD
1 part chloride 50 parts nitrite CD
1 part chlorite 100 parts fluoride CD
1 part chlorite 10 parts fluoride UV
1 part chlorite 1 000 parts carbonate CD
1 part chlorite 1 000 parts chloride CD / UV / AD
1 part chlorite 100 parts nitrite AD
a
In case the quality requirements in Clause 8 (e.g. see Figures 2 and 3) are not achieved, the sample shall be diluted.
5 Principle
Liquid chromatographic separation of chlorate, chloride and chlorite is carried out by means of a
separator column. A low-capacity anion exchanger is used as the stationary phase and usually aqueous
solutions of salts of weak mono- and dibasic acids as mobile phases (eluent, 6.8).
Detection is by CD with or without suppressor device, UV or AD.
When using conductivity detectors, it is essential that the eluents have a sufficiently low conductivity.
For this reason, conductivity detectors are often combined with a suppressor device (cation exchangers)
ISO 10304-4:2022(E)
which reduces the conductivity of the eluent and transforms the sample species into their respective
acids.
UV detection measures the absorption directly or indirectly.
Amperometric detection of chlorite is carried out via measurement of the current generated by the
oxidation of chlorite. The oxidation voltage for chlorite depends on the pH of the eluent. The use of
carbon electrodes has proved successful.
The concentration of the respective anions is determined by a calibration of the overall procedure.
Particular cases may require calibration by means of standard addition (spiking). Control experiments
are necessary to check the validity of the calibration function. Replicate determinations can be
necessary.
6 Reagents
Use only reagents of recognized analytical grade. Carry out weighing with an accuracy of 1 % of the
nominal mass. An increase in electrical conductivity due to an uptake of carbon dioxide does not
interfere with the determination. Use and prepare alternative concentrations or volumes of solutions
as described below, if necessary. Alternatively, use commercially available solutions of the required
specification.
6.1 Water.
The water used shall have a resistivity ≥18 MΩ·cm (25 °C) and shall not contain particulate matter of a
particle size >0,45 µm.
6.2 Sodium hydrogencarbonate, NaHCO .
6.3 Sodium carbonate, Na CO .
2 3
6.4 Sodium hydroxide solution, c(NaOH) = 0,1 mol/l.
6.5 Sodium chlorite, NaClO (80 %).
6.6 Sodium chloride, NaCl.
6.7 Sodium chlorate, NaClO .
6.8 Eluents.
Degas all eluents used. Take steps to avoid any renewed air pick up during operation (e.g. by helium
sparging, inline degasser).
The choice of eluent (e.g. based on sodium carbonate or sodium hydroxide solutions, potassium
hydroxide, mixed with organic modifiers, if needed) depends on the choice of column and detector;
seek advice from the column supplier. Apply eluents that were prepared: manually, by inline dilution or
electrochemically in situ. The chosen combination of separator column and eluent shall conform to the
resolution requirements stated in Clause 7. Use eluents as long as the requirement in Clause 8 is met.
An example for an appropriate eluent manually prepared is given in 6.8.2.
ISO 10304-4:2022(E)
6.8.1 Sodium carbonate/sodium hydrogencarbonate concentrate.
For the eluent concentrate preparation:
— Place 19,1 g of sodium carbonate (6.3) and 14,3 g of sodium hydrogencarbonate (6.2) into a volumetric
flask of nominal capacity 1 000 ml, dissolve in water (6.1) and dilute to volume with water (6.1).
— The solution contains 0,18 mol/l of sodium carbonate and 0,17 mol/l of sodium hydrogencarbonate.
This solution is stable for several months if stored at 2 °C to 6 °C.
6.8.2 Sodium carbonate/sodium hydrogencarbonate eluent.
The following eluent is applicable for the determination of chlorate, chloride and chlorite:
— Pipette 50 ml of the sodium carbonate/sodium hydrogencarbonate concentrate (6.8.1) into a
volumetric flask of nominal capacity 5 000 ml and dilute to volume with water (6.1).
— The solution contains 0,001 8 mol/l of sodium
...