FprEN ISO 18127
(Main)Water quality - Determination of adsorbable organically bound fluorine, chlorine, bromine and iodine (AOF, AOCl, AOBr, AOI) - Method using combustion and subsequent ion chromatographic measurement (ISO/FDIS 18127:2025)
Water quality - Determination of adsorbable organically bound fluorine, chlorine, bromine and iodine (AOF, AOCl, AOBr, AOI) - Method using combustion and subsequent ion chromatographic measurement (ISO/FDIS 18127:2025)
This dcoument specifies a method for the determination of fluoro-, chloro-, bromo- and iodo-organic compounds (AOF, AOCl, AOBr, AOI). Due to the high solubility of AgF in water the scope of ISO 9562 is restricted to Cl-, Br- and I-organic compounds (AOX, calculated as chlorine) because of the applied argentometric detection. The PN follows the proven AOX ISO 9562 method: adsorption of organohalogen
compounds on activated carbon, oxidative combustion at 1000 °C with following alterations: constant water feed during combustion (hydropyrolysis), absorption of combustion gases in water, halide specific detection using ionchromatography. The method is applicable for the determination of
2 µg/l AOF, expressed as F
10 µg/l AOCl, expressed as Cl
1 µg/l AOBr, expressed as Br
1 µg/l AOI, expressed as I.
Samples for determination of AOF are treated differently than samples for the determination of AOCl,
AOBr and AOI.
- Samples for determination of AOF are not acidified. The adsorption takes place under unchanged pH
conditions. Washing is also performed with a neutral washing solution.
- Samples for the determination of AOCl, AOBr and AOI are adjusted to a pH value 2 with nitric acid,
the adsorption and washing take place in a nitric acid environment.
Wasserbeschaffenheit - Bestimmung von adsorbierbarem organisch gebundenem Fluor, Chlor, Brom und Iod (AOF, AOCl, AOBr, AOI) - Verfahrens mittels Verbrennung und nachfolgender Ionenchromatographischer Messung (ISO/FDIS 18127:2025)
Qualité de l’eau - Dosage des composés organiques adsorbables contenant du fluor, du chlore, du brome et de l’iode (AOF, AOCl, AOBr, AOI) - Méthode de combustion suivie d’un mesurage par chromatographie ionique (ISO/FDIS 18127:2025)
Kakovost vode - Določanje organsko vezanega fluora, klora, broma in joda, sposobnega adsorpcije (AOF, AOCl, AOBr, AOI) - Metoda z zgorevanjem in ionsko kromatografijo (ISO/FDIS 18127:2025)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 18127:2024
01-september-2024
Kakovost vode - Določanje organsko vezanega fluora, klora, broma in joda,
sposobnega adsorpcije (AOF, AOCl, AOBr, AOI) - Metoda z zgorevanjem in ionsko
kromatografijo (ISO/DIS 18127:2024)
Water quality - Determination of adsorbable organically bound fluorine, chlorine, bromine
and iodine (AOF, AOCl, AOBr, AOI) - Method using combustion and subsequent ion
chromatographic measurement (ISO/DIS 18127:2024)
Wasserbeschaffenheit - Bestimmung von adsorbierbarem organisch gebundenem Fluor,
Chlor, Brom und Iod (AOF, AOCl, AOBr, AOI) - Verfahrens mittels Verbrennung und
nachfolgender Ionenchromatographischer Messung (ISO/DIS 18127:2024)
Qualité de l'eau - Dosage du fluor, du chlore, du brome et de l'iode adsorbables liés
organiquement (AOF, AOCl, AOBr, AOI) - Méthode en utilisant la combustion et la
mesure ultérieure par chromatographie ionique (ISO/DIS 18127:2024)
Ta slovenski standard je istoveten z: prEN ISO 18127
ICS:
13.060.50 Preiskava vode na kemične Examination of water for
snovi chemical substances
oSIST prEN ISO 18127:2024 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN ISO 18127:2024
oSIST prEN ISO 18127:2024
DRAFT
International
Standard
ISO/DIS 18127
ISO/TC 147/SC 2
Water quality — Determination
Secretariat: DIN
of adsorbable organically bound
Voting begins on:
fluorine, chlorine, bromine and
2024-07-05
iodine (AOF, AOCl, AOBr, AOI) —
Voting terminates on:
Method using combustion and
2024-09-27
subsequent ion chromatographic
measurement
Qualité de l'eau — Dosage du fluor, du chlore, du brome et de
l'iode adsorbables liés organiquement (AOF, AOCl, AOBr, AOI) —
Méthode en utilisant la combustion et la mesure ultérieure par
chromatographie ionique
ICS: 13.060.50
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
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USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
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WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
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NOTIFICATION OF ANY RELEVANT PATENT
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PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 18127:2024(en)
oSIST prEN ISO 18127:2024
DRAFT
ISO/DIS 18127:2024(en)
International
Standard
ISO/DIS 18127
ISO/TC 147/SC 2
Water quality — Determination
Secretariat: DIN
of adsorbable organically bound
Voting begins on:
fluorine, chlorine, bromine and
iodine (AOF, AOCl, AOBr, AOI) —
Voting terminates on:
Method using combustion and
subsequent ion chromatographic
measurement
Qualité de l'eau — Dosage du fluor, du chlore, du brome et de
l'iode adsorbables liés organiquement (AOF, AOCl, AOBr, AOI) —
Méthode en utilisant la combustion et la mesure ultérieure par
chromatographie ionique
ICS: 13.060.50
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2024
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
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BE CONSIDERED IN THE LIGHT OF THEIR
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Published in Switzerland Reference number
ISO/DIS 18127:2024(en)
ii
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Interferences . 3
4.1 Interference during adsorption .3
4.2 Interferences on combustion .3
4.3 Interferences on ion chromatography .3
5 Principle . 3
6 Reagents . 4
7 Apparatus and materials . 8
8 Sampling and sample preparation .11
8.1 General .11
8.2 Sampling for the AOF determination .11
8.3 Sampling for the AOCl-, AOBr- and AOI determination .11
8.4 Further procedure of sample preparation .11
8.4.1 AOF determination .11
8.4.2 AOCl, AOBr and AOI determination. 12
9 Procedure .12
9.1 Preliminary test . 12
9.2 Homogenization. 12
9.3 Sample preparation . 13
9.3.1 General . 13
9.3.2 Test sample for the AOF determination . 13
9.3.3 Test samples for the AOCl, AOBr and AOI determination . 13
9.4 Adsorption on activated carbon . 13
9.4.1 Washing of the activated carbon for the AOF determination . 13
9.4.2 Washing of the activated carbon for the AOCl, AOBr, AOI determination . 13
9.5 Additional procedure . 13
9.6 Blank determination .14
9.6.1 AOF blank determination .14
9.6.2 AOCl, AOBr and AOI blank determination .14
9.7 Consideration of matrix contributions to AOF, AOCl, AOBr, AOI .14
9.8 Operation of the ion chromatography system .14
9.8.1 General .14
9.8.2 Calibration . . .14
9.8.3 Measurement . 15
9.8.4 Checking the ion chromatography . 15
9.9 Combustion and absorption . 15
9.10 Measurement of the absorption solution . 15
10 Validation of the overall procedure . .15
10.1 Initial check . 15
10.2 Daily check .16
10.3 Test to determine the completeness of the adsorption .16
11 Selection of usable analytical results .16
12 Calculation .16
13 Expression of the results . 17
14 Test report .18
iii
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
Annex A (normative) Determination of adsorbable organically bound fluorine (AOF) . 19
Annex B (normative) Determination of adsorbable organically bound chlorine (AOCl) .22
Annex C (normative) Determination of adsorbable organically bound bromine (AOBr) .25
Annex D (normative) Determination of the adsorbable organically bound iodine (AOI) .29
Annex E (informative) Determination of adsorbable organically bound fluorine, chlorine,
bromine and iodine using the shaking procedure (SH-AOF, SH-AOCl, SH-AOBr, SH-AOI) .33
Annex F (informative) Determination of adsorbable organically bound fluorine, chlorine,
bromine and iodine in waters with high halide contents after solid phase extraction
(SPE-AOF, SPE-AOCl, SPE-AOBr, SPE-AOI) .36
Annex G (normative) Test to determine the completeness of the adsorption by individual
combustion of the activated carbons from the multiple determinations and separate
absorption .39
Annex H (normative) Test to determine the completeness of the adsorption by common
combustion of the activated carbons from different dilution levels .40
Annex I (normative) Test to determine the completeness of the adsorption by adsorption on
columns connected in series with different quantities of adsorption columns . 41
Annex J (normative) Calculation of the CIC-AOX from the AOCl, AOBr and AOI results added
(Cl)
according to Annex B, Annex C and Annex D.42
Annex K (informative) Performance data .43
Bibliography .45
iv
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
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,
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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).
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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.
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.
v
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
Introduction
Adsorbable organically bound fluorine, chlorine, bromine or iodine are analytical convention parameters
used to monitor water quality.
They represent the sum of organically bound fluorine, chlorine, bromine and iodine that can be adsorbed on
activated carbon under specified conditions and, if the sample has not been filtered, can also be attached to
or contained in suspended substances.
In contrast to the AOX method according to ISO 9562, this method can be applied to determine the sum
of organofluorine compounds in addition to the determination of organically bound chlorine, bromine and
iodine and detected halogen-specific separately.
The method is carried out by combustion ion chromatography (CIC).
vi
oSIST prEN ISO 18127:2024
DRAFT International Standard ISO/DIS 18127:2024(en)
Water quality — Determination of adsorbable organically
bound fluorine, chlorine, bromine and iodine (AOF, AOCl,
AOBr, AOI) — Method using combustion and subsequent ion
chromatographic measurement
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 organically bound halogens fluorine, chlorine,
bromine and iodine which are adsorbable on activated carbon. Adsorption takes place on activated carbon
packed in columns.
The method is applicable for the determination of:
— ≥ 2 µg/l AOF, expressed as F;
— ≥ 10 µg/l AOCl, expressed as Cl;
— ≥ 1 µg/l AOBr, expressed as Br;
— ≥ 1 µg/l AOI, expressed as I.
The method is applicable for the determination of adsorbable organically bound fluorine, chlorine, bromine
or iodine in water, e.g. in groundwater, surface water, bank filtrate, drinking water, aqueous eluates, cooling
water and wastewater.
The working range is limited by the capacity of the activated carbon, the process blank and the capacity of
the chromatographic separation column. Sample dilution into the working range can be required.
The method can also be applied for samples containing suspended matter. Halogens adsorbed on the
suspended solids (e.g. undissolved halides) are determined, too. Filtration of the sample prior to analyses
using a membrane filter (0,45 µm) allows the separate determination of dissolved adsorbable and particulate
bound fractions of organically bound fluorine, chlorine, bromine or iodine.
Procedures for each separate parameter are described in normative Annex A, Annex B, Annex C and Annex D.
Alternatively, the adsorption of the organic substances contained in the water sample on activated carbon
can also be carried out by the shaking method (see Annex E).
Samples with a high content of inorganic halides can be analysed using the solid phase extraction (SPE)
method (see Annex F).
Results for samples analysed according to Annex E (shaking procedure) or Annex F (SPE procedure) can
differ significantly from those of the method specified in the main part.
With some waters, interference can occur that cannot be eliminated. These waters cannot be measured with
the method.
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
The AOCl, AOBr and AOI results according to Annex B, Annex C and Annex D can also be reported as
CIC-AOX (Annex J).
(Cl)
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 8466-2, Water quality — Calibration and evaluation of analytical methods and estimation of performance
characteristics — Part 2: Calibration strategy for non-linear second-order calibration functions
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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/
3.1
adsorbable organically bound fluorine
AOF
equivalent mass of fluorine in organic halogen compounds, expressed as fluorine, measured under the
conditions of this procedure
3.2
adsorbable organically bound chlorine
AOCl
equivalent mass of chlorine in organic halogen compounds, expressed as chlorine, measured under the
conditions of this procedure
3.3
adsorbable organically bound bromine
AOBr
equivalent mass of bromine in organic halogen compounds, expressed as bromine, measured under the
conditions of this procedure
3.4
adsorbable organically bound iodine
AOI
equivalent mass of iodine in organic halogen compounds, expressed as iodine, measured under the
conditions of this procedure
3.5
adsorbable organically bound halogens
AOX
equivalent mass of the halogens chlorine, bromine and iodine in organic compounds, determined according
to ISO 9562 and expressed as chloride
3.6
test sample
sample obtained from the original sample after preparation and dilution, if necessary and fed into the
adsorption process
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
3.7
combustion ion chromatography
CIC
technique comprising oxidative high-temperature combustion followed by absorption of formed hydrogen
halides and subsequent ion chromatographic detection of the halide ions
3.8
CIC-AOX
equivalent mass of chlorine, bromine and iodine representing the sum of organically bound chlorine, bromine
and iodine. measured under the conditions of this method; expression of results as mass concentration of
chlorine
4 Interferences
4.1 Interference during adsorption
Sample matrix characteristics (e.g. high concentrations of dissolved carbon (DOC) can cause interference
with the adsorption of the organically bound halogens and result in negative bias). These effects can be
solved by sample dilution or spiking experiments, if necessary. Information on the influence of DOC on the
adsorption reaction of the sample can be provided by current measurements or previous testing of the
sampling point. For samples not filtered, the total organic carbon (TOC) can also be used as information.
Samples containing living cells (e.g. microorganisms or algae) can cause a positive bias due to their halide
content on AOCl, AOBr and AOI (chloride, bromide, and iodide). In this case, the acidified sample is analysed
at least the earliest 8 h after sampling.
Particulate inorganic halogen compounds with a melting point < 1 000 °C cause a positive bias.
The recovery of some polar and hydrophilic compounds, e.g. trifluoroacetate or monochloroacetate, is
incomplete.
High contents of undissolved substances can cause interference with the column method. In these cases, the
use of the shaking procedure (Annex E) should be considered.
Contamination of the laboratory air due to chemicals or other sources can cause positive bias.
4.2 Interferences on combustion
Alkali metals present can cause premature devitrification of a quartz glass combustion tube.
NOTE The use of a ceramic inner tube can increase the lifetime of the combustion tube significantly.
Missing or too little water supply in the AOF determination can cause a negative bias.
4.3 Interferences on ion chromatography
Any substance that generates a detector signal similar to that of the analyte ion can cause interference.
Additionally, a high concentration of ions can influence the peak resolution and the retention time of the
analyte. Gradient elution canminimize many of these interferences.
5 Principle
Basic requirements for the procedure are:
— Samples for the determination of AOF are treated differently from samples for the determination of AOCl,
AOBr and AOI.
— Samples for the determination of AOF are not acidified. The adsorption takes place under unchanged pH
conditions. Washing is performed with a neutral washing solution.
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
— Samples for the determination of AOCl, AOBr and AOI are adjusted to a pH < 2 with nitric acid. The
adsorption and washing step are carried out in a nitric acid environment
— The aqueous sample is passed through columns of activated carbon which adsorbs the organically bound
halogens.
— The inorganic halides are removed by washing with a nitrate solution
— The activated carbon is combusted in an oxygen stream at 950 °C or higher.
For the determination of AOF, the loaded activated carbon is combusted with addition of water
(hydropyrolysis)
— The resulting change in the volume in the absorption solution is taken into account when calculating of
the concentration (e.g. by determining the recovery of an internal standard).
— The hydropyrolytic combustion does not interfere with the determination of AOCl, AOBr and AOI.
— The resulting hydrogen halide ions from the organically bound halogens are collected in an absorbing
solution
The absorbing solution is injected into an ion chromatograph with a suppressed conductivity detector
where anions are separated and quantitated. The ion chromatographic separation is carried out on an anion
exchange resin as stationary phase. Aqueous solutions of salts of weak monobasic and dibasic acids are used
as eluents for isocratic or gradient elution. Determination is carried out by means of conductivity detection
(CD). The conductivity of the eluents is reduced by a suppressor device (cation exchanger). UV or Tandem UV
detection may be used.
NOTE A UV detector is not required to perform this analysis, but it can be used for bromide and iodide if higher
sensitivity is required or in the case of matrix interference with the CD. UV detection (UVD) can be used in combination
with the CD. The UV detector measures the absorption of the irradiated UV radiation. The measuring wavelength is at
λ = (215 ± 10) nm for bromide and at λ = (226 ± 10) nm for iodide.
6 Reagents
6.1 General
Use only reagents with the purity grade "for analyses", if available. Unless otherwise stated, reagents shall
be weighed to an accuracy of ±1 % of nominal mass. Commercially available solutions of equivalent quality
may be used. If necessary, alternative volumes and concentrations to the solutions described in this clause
may be prepared and used.
All reagents shall be checked for their contribution to the blank, if applicable.
6.2 Water, with a specific electrical resistance of ≥ 18 MΩ�⋅ cm (25 °C).
6.3 Reagents for sample stabilization and pre-treatment.
6.3.1 Nitric acid, w(HNO ) = 65 %.
6.3.2 Sodium sulfite, Na SO .
2 3
6.3.2.1 Sodium sulfite solution, c(Na SO ) = 1 mol/l.
2 3
Dissolve 126 g Na SO (6.3.2) in water (6.2) in a 1 000 ml volumetric flask and dilute to volume with
2 3
water (6.2).
The solution is stable for four weeks if stored at (5 ± 3) °C.
6.3.3 Iodine starch paper.
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
6.3.4 Potassium iodide.
6.3.5 Starch solution, mass fraction 1 %.
6.4 Reagents and gases for adsorption, combustion and absorption.
6.4.1 Activated carbon with an iodine number > 1 050 mg/g.
Suitable natural coal-derived activated carbons have particle sizes in the range of about 50 µm to 150 µm.
Synthetic materials with larger specific surfaces may also be used.
Various methods can be used to determine the adsorption capacity. One of these methods is described, e.g.
in EN 12902. The iodine number gives an indication of the adsorption capacity of the activated carbon.
NOTE 1 Activated carbon qualities with grain sizes < 50 µm can lead to blockage of the adsorption column.
NOTE 2 To prevent the activated carbon from being contaminated by adsorption of halogen-containing compounds
from the laboratory air during storage, the activated carbon should be stored in an airtight container (e.g. aluminium
screw bottle, halogen polymer-free plastic bottle, or similar). Only the daily required amount for the intended series
or samples should be taken from a separate container. The remainder of the activated carbon taken from the container
each day should be discarded. Any additional activated carbon not used within the same day shall be discarded.
NOTE 3 The halogen blank values of the activated carbon can be determined by analysing e.g. 100 mg of the
activated carbon analyses moistened with 100 µl water (6.2). The result serves as an indication of relevant impurities.
Ultimately, the analytically decisive factor is the method blank.
The applicability of an activated carbon batch shall be checked on the recoveries of fluorine, chlorine,
bromine or iodine from model substances via the overall procedure given in Annex A, Annex B, Annex C and
Annex D. The compounds listed in Annex A, Annex B, Annex C and Annex D shall be used as test reagents.
6.4.2 Sodium nitrate, NaNO .
6.4.2.1 Neutral nitrate stock solution I, c(NaNO ) = 2 mol/l for the AOF determination.
Dissolve 170 g sodium nitrate (6.4.2) in water (6.2) in a 1 000 ml volumetric flask and dilute to volume with
water (6.2).
The solution is stable for six months if stored in an amber glass bottle.
6.4.2.2 Neutral nitrate wash solution II, c(NaNO ) = 0,01 mol/l for the AOF determination.
Pipette 5 ml of neutral nitrate stock solution (6.5.2.1) in a 1 000 ml volumetric flask and dilute to volume
with water (6.2).
The solution is stable for four weeks if stored in an amber glass bottle.
6.4.2.3 Nitric acid nitrate stock solution I, c(NaNO ) = 2 mol/l for the AOCl, AOBr and AOI determination
Dissolve 170 g sodium nitrate (6.5.2) in water (6.2) in a 1 000 ml volumetric flask, add 25 ml nitric acid
(6.4.1) and dilute to volume with water (6.2).
The solution is stable for six months if stored in an amber glass bottle.
6.4.2.4 Nitric acid nitrate wash solution II, c(NaNO ) = 0,01 mol/l, pH ≈ 1,7 for the AOCl, AOBr and AOI
determination.
Pipette 5 ml of nitric acid stock solution (6.4.2.3) in a 1 000 ml volumetric flask and dilute to volume with
nitric acid dilution water (6.4.6).
The solution is stable for four weeks if stored in an amber glass bottle.
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
6.4.3 Ethanol, C H OH, absolute.
2 5
6.4.4 Standard solutions for the test of the overall procedure
Organic single and multi-component stock solutions with appropriate and required specification may be
used if commercially available. These solutions are stable for six months. The manufacturer specifications
shall be observed. Alternatively, stock solutions may be prepared by weighing. See Annex A, Annex B,
Annex C and Annex D.
6.4.5 Dilution water and blank solution for the determination of the total AOF blank value 100 ml
water (6.2).
6.4.6 Nitric acid dilution water and blank solution for the determination of the total AOCl, AOBr and
AOI blanks
100 ml water (6.2), acidified with 0,2 ml nitric acid (6.3.1).
6.4.7 Oxygen, or a mixture of oxygen and inert gas (e.g. argon)
NOTE 1 Gas purities for oxygen ≥ 99,995 % and argon ≥ 99,998 % have proven to be sufficient.
NOTE 2 The use of argon is recommended when using adsorption columns packed with cellulose wool. Adsorption
columns packed with ceramic wool or quartz wool can possibly be combusted without the use of an inert gas. For a
residue-free conversion of e.g. cellulose wool packed adsorption columns, an inert gas (e.g. argon) should be used.
Otherwise, incomplete combustion, resulting in incorrect results can occur.
6.4.8 Absorption solution for combustion gases
Water (6.2). Alternatively, solutions according to C.5.5 and D.5.5 may be prepared for absorption.
The use of an internal standard in the absorption solution is necessary if the volume of the absorption solution
cannot be determined prior to sample injection into the ion chromatography. For example, methanesulfonic
acid or phosphate solutions can be used as internal standards (6.5.5).
NOTE The addition of reducing agents, e.g. hydrogen peroxide in an alkaline medium, can be necessary for the
determination of bromine and iodine (C.5.5 and D.5.5).
6.5 Reagents for the ion chromatography
6.5.1 Eluents
Carbonate, hydrogen carbonate, hydroxide salts, e.g. manually, automatically or electrochemically generated
in situ, may be used as eluents. The choice of eluent depends on the selected separation column and detector;
follow the column manufacturer's instructions. The selected combination of separation column and eluent
shall fulfil the requirement for the peak resolution according to 7.8. The eluents may be used as long as the
requirements according to 7.8 are fulfilled. An example of a suitable eluent is described in 6.5.2.2.
Degas the eluents, if necessary. A renewed gas uptake shall be prevented during operation (e.g. by helium
overlay or inline degasser).
6.5.2 Sodium carbonate, Na CO
2 3
6.5.2.1 Sodium carbonate concentrate, c(Na CO ) = 0,09 mol/l.
2 3
Dissolve 9,54 g sodium carbonate (6.5.2) in water (6.2) in a 1 000 ml volumetric flask and dilute to volume
with water (6.2).
The solution is stable for six months if stored at (5 ± 3) °C.
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
6.5.2.2 Sodium carbonate eluent, c(Na CO ) = 0,009 mol/l.
2 3
The following eluent is suitable for the determination of the ions mentioned in 6.5.3: Pipette 100 ml of the
sodium carbonate concentrate (6.5.2.1) into a 1 000 ml volumetric flask and dilute to volume with water (6.2).
6.5.3 Fluoride, chloride, bromide and iodide stock solutions, each ρ = 1 000 mg/l.
Single anion and mixed anion stock solutions with adequate and required specifications are commercially
available. These solutions are considered to be stable for several months. Alternatively, prepare stock
solutions manually according to Table 1. The salts are dissolved accordingly in water (6.2) after adequate
drying. Use mixed standard solutions in suitable concentrations with at least five different concentrations
for the calibrations.
Table 1 — Weighing and pre-treatment for the stock solutions
a
Anion Salt Weighing (g) Dry salt at (105 ± 5) °C for at least
in 1 000 ml
Fluoride NaF 2,210 1 h
Chloride NaCl 1,648 2 h
Bromide NaBr 1,288 6 h
Iodide NaI 1,181 3 h
a
Other salts that meet the required specifications may be used.
6.5.4 Fluoride, chloride, bromide and iodide calibration solution.
6.5.4.1 General
Depending on the expected concentrations, single or mixed standard solutions with fluoride, chloride,
bromide and iodide contents are to be prepared from the stock solutions (6.5.3). The following example
describes the preparation of mixed standard solutions.
The standard solutions shall be stored in polyethene or glass containers.
6.5.4.2 Example of a fluoride, chloride, bromide and iodide mixed standard solution, each
ρ = 10 mg/l.
Pipette 1,0 ml of each of the stock solutions (6.5.3) into a 100 ml volumetric flask and dilute to volume with
water (6.2).
The solution is stable for one week if stored in polyethene containers at (5 ± 3) °C.
6.5.4.3 Fluoride, chloride, bromide and iodide calibration solution
Depending on the expected concentrations in the sample, prepare e.g. five to ten calibration solutions
distributed as evenly as possible over the expected working range, from the mixed standard solution
(6.5.4.2).
For the range of e.g. 0,05 mg/l to 0,5 mg/l proceed as follows:
Place the following volumes in a series of 20 ml volumetric flasks:
Pipette 100 μl, 200 μl, 300 μl, 400 μl, 500 μl, 600 μl, 700 μl, 800 μl, 900 μl and 1 000 μl of the mixed standard
solution (6.5.4. 2) and dilute to volume with water (6.2).
The anion concentrations in these calibration solutions are: 0,05 mg/l; 0,1 mg/l; 0,15 mg/l; 0,2 mg/l;
0,25 mg/l; 0,3 mg/l; 0,35 mg/l; 0,4 mg/l; 0,45 mg/l and 0,5 mg/l.
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
The solutions shall be prepared on the day of use.
NOTE For assessment of any possible chromatographic interference by coeluting ions, addition anions, e.g.
nitrate, sulfate or phosphate to the calibration solution should be carried out. It is useful to check possible coelution
with iodate, bromate, nitrite, sulfite, chlorite and chlorate.
6.5.5 Internal standard
Sodium methane sulphonate or phosphate solutions, e.g. can be used as an internal standard. Clause 6.5.5.3
describes the preparation of a sodium methanesulfonate solution as an example of a suitable internal
standard.
6.5.5.1 Sodium methanesulfonate, CH SO Na.
3 3
6.5.5.2 Sodium methanesulfonate solution, ρ(CH SO Na) = 500 mg/l.
3 3
Dissolve 500 mg sodium methanesulfonate (6.5.5.1) in the absorption solution (6.4.8) in 1 000 ml volumetric
flask and dilute to volume with absorption solution (6.4.8).
6.5.5.3 Absorption solution with internal standard sodium methanesulfonate, ρ(CH SO Na) = 1 mg/l.
3 3
Pipette 2 ml of the sodium methanesulfonate solution (6.5.5.2) in 1 000 ml volumetric flask and dilute to
volume with absorption solution (6.4.8).
The solution is stable for three months if stored at (5 ± 3) °C.
6.5.6 Blank solution for the ion chromatography
Fill a volumetric flask with water (6.2), e.g. 100 ml.
7 Apparatus and materials
7.1 General
Care should be taken to ensure that, in accordance with the objective of the analyses. It is important to
ensure that only those materials are used that do not generate a significant contribution to the blank value
(e.g. use of halogen-free materials for e.g. valves, tubes, etc.).
Usual laboratory equipment and in particular the following.
7.2 Filtration device, e.g. with a filter funnel, capacity V = 0,15 l, filter diameter 25 mm, filtration unit for
positive or negative pressure filtration.
7.3 Polycarbonate membrane filter, e.g. of diameter 25 mm and pore size 0,45 µm, or equivalent filter
material.
7.4 Device for adsorption on activated carbon applying the column procedure.
Suitable pump, e.g. piston pump with polypropylene transfer tubing and a device (e.g. automatic sample
changer) for homogeneous sample transfer, which is equipped with a stirring device, e.g. magnetic stirrer,
adsorption columns, inner diameter e.g. about 3 mm, length 40 mm to 50 mm, packed with activated carbon
and arranged vertically in series. Other column dimensions are possible. Apply the sample to the top of the
columns and pass it through the column with excess pressure.
7.5 Ceramic wool, or cellulose wool or other suitable material, for fixing the activated carbon in the
columns.
oSIST prEN ISO 18127:2024
ISO/DIS 18127:2024(en)
7.6 Device for combustion and absorption
7.6.1 Combustion device, consisting of a furnace, heatable to 950 °C or higher, with a quartz glass or
ceramic combustion tube . Both tubes, vertically and horizontally arranged combustion, are suitable. To
determine AOF, a combustion device with a device for hydropyrolysis is required (example see Figure 1).
Key
1 inlet for water, combustion and inert gas 6 inner combustion tube
2 sample inlet 7 sample boat
3 combustion gas inlet 8 absorption vessel
4 furnace 9 ion chromatograph
5 outer combustion tube
Figure 1 — Schematic representation of a device for the combustion with hydropyrolysis and
coupled ion chromatograph
NOTE For trace analyses and to reduce contamination risks, e.g. by decanting the absorption solution or by
contact of the absorption solution with laboratory air, it is recommended to fill the absorption tube (7.6.3) and the
injection loop (7.7.4) and to flush the gas-transfer lines between the combustion tube (7.6.2) and the absorption tube
(7.6.3) in a closed system and to couple the combustion apparatus and the ion chromatograph via an injection valve.
7.6.2 Sample boat, e.g. ceramic or quartz container, suitable to be inserted into the combustion tube.
7.6.3 Absorption tube, with a suitable volume of the absorp
...
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