Water quality - Determination of dissolved perchlorate - Method using ion chromatography (IC) (ISO 19340:2017)

ISO 19340:2017 specifies a method for the determination of dissolved perchlorate in water (e.g. drinking water, mineral water, raw water, surface water, partially treated water or swimming pool water, waste water from drinking/swimming pool water treatment plants).
Appropriate pre-treatment of the sample (e.g. matrix elimination) allows a direct determination of perchlorate ≥ 1 µg/l.
The working range is restricted by the ion-exchange capacity of the separator column. Dilution of the sample to the working range can be necessary.

Wasserbeschaffenheit - Bestimmung von gelöstem Perchlorat - Verfahren mittels Ionenchromatographie (IC) (ISO 19340:2017)

Dieses Dokument legt ein Verfahren zur Bestimmung von gelöstem Perchlorat in Wasser (z. B. Trinkwasser, Mineralwasser, Rohwasser, Oberflächenwasser, teilweise behandeltes Wasser oder Badebeckenwasser, Abwasser aus Trink-/Badebeckenwasser-Behandlungsanlagen) fest.
Eine geeignete Probenvorbehandlung (z. B. Matrixentfernung) erlaubt die direkte Bestimmung von Perchlorat-Konzentrationen ≥ 1 µg/l.
Der Arbeitsbereich ist durch die Ionenaustauschkapazität der Trennsäule begrenzt. Eine Probenverdünnung in den Arbeitsbereich kann erforderlich sein.

Qualité de l'eau - Détermination du perchlorate dissous - Méthode par chromatographie ionique (IC) (ISO 19340:2017)

L'ISO 19340 :2017 spécifie une méthode de détermination du perchlorate dissous dans l'eau (par exemple, dans l'eau potable, l'eau minérale, l'eau brute, l'eau de surface, l'eau partiellement traitée ou l'eau de piscine, les eaux usées des stations de traitement d'eau potable/d'eau de piscine).
Un pré-traitement approprié de l'échantillon (par exemple, l'élimination de la matrice) permet une détermination directe du perchlorate ≥ 1 µg/l.
Le domaine d'analyse est limité par la capacité d'échange d'ions de la colonne de séparation. Une dilution de l'échantillon pour rester dans le domaine d'analyse peut s'avérer nécessaire.

Kakovost vode - Določevanje raztopljenega perklorata - Metoda z ionsko kromatografijo (IC) (ISO 19340:2017)

Ta mednarodni standard določa metodo za določevanje raztopljenega perklorata v vodi (npr. pitna, mineralna, surova, površinska, delno pripravljena ali bazenska voda, odpadna voda iz čistilne naprave za pitno/bazensko vodo). Ustrezna predobdelava vzorca (npr. eliminacija matrice) omogoča neposredno določevanje perklorata ≥1 μg/l. Delovni obseg je omejen z zmogljivostjo ionske izmenjave separatorske kolone. Morda je potrebno redčenje vzorca do delovnega obsega.

General Information

Status
Published
Publication Date
05-Dec-2017
Technical Committee
Drafting Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
06-Dec-2017
Completion Date
06-Dec-2017

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SLOVENSKI STANDARD
SIST EN ISO 19340:2018
01-junij-2018
.DNRYRVWYRGH'RORþHYDQMHUD]WRSOMHQHJDSHUNORUDWD0HWRGD]LRQVNR
NURPDWRJUDILMR ,&  ,62
Water quality - Determination of dissolved perchlorate - Method using ion
chromatography (IC) (ISO 19340:2017)
Wasserbeschaffenheit - Bestimmung von gelöstem Perchlorat - Verfahren mittels
Ionenchromatographie (IC) (ISO 19340:2017)

Qualité de l'eau - Détermination du perchlorate dissous - Méthode par chromatographie

ionique (IC) (ISO 19340:2017)
Ta slovenski standard je istoveten z: EN ISO 19340:2017
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
SIST EN ISO 19340:2018 en,fr,de

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

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SIST EN ISO 19340:2018
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SIST EN ISO 19340:2018
EN ISO 19340
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2017
EUROPÄISCHE NORM
ICS 13.060.50
English Version
Water quality - Determination of dissolved perchlorate -
Method using ion chromatography (IC) (ISO 19340:2017)

Qualité de l'eau - Détermination du perchlorate dissous Wasserbeschaffenheit - Bestimmung von gelöstem

- Méthode par chromatographie ionique (IC) (ISO Perchlorat - Verfahren mittels Ionenchromatographie

19340:2017) (IC) (ISO 19340:2017)
This European Standard was approved by CEN on 7 October 2017.

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

© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19340:2017 E

worldwide for CEN national Members.
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SIST EN ISO 19340:2018
EN ISO 19340:2017 (E)
Contents Page

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

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SIST EN ISO 19340:2018
EN ISO 19340:2017 (E)
European foreword

This document (EN ISO 19340:2017) 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 June 2018, and conflicting national standards shall be

withdrawn at the latest by June 2018.

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.

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 19340:2017 has been approved by CEN as EN ISO 19340:2017 without any modification.

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SIST EN ISO 19340:2018
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SIST EN ISO 19340:2018
INTERNATIONAL ISO
STANDARD 19340
First edition
2017-10
Water quality — Determination of
dissolved perchlorate — Method using
ion chromatography (IC)
Qualité de l'eau — Détermination du perchlorate dissous — Méthode
par chromatographie ionique (IC)
Reference number
ISO 19340:2017(E)
ISO 2017
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SIST EN ISO 19340:2018
ISO 19340:2017(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior

written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of

the requester.
ISO copyright office
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Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved
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SIST EN ISO 19340:2018
ISO 19340:2017(E)
Contents Page

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

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

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

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

4 Interferences ............................................................................................................................................................................................................ 1

5 Principle ........................................................................................................................................................................................................................ 2

6 Reagents ........................................................................................................................................................................................................................ 2

7 Apparatus ..................................................................................................................................................................................................................... 4

8 Quality requirements ...................................................................................................................................................................................... 5

8.1 Performance of the separator column ................................................................................................................................ 5

8.2 Materials ....................................................................................................................................................................................................... 6

9 Sampling and sample pre-treatment .............................................................................................................................................. 6

10 Procedure..................................................................................................................................................................................................................... 7

10.1 General ........................................................................................................................................................................................................... 7

10.2 Calibration .................................................................................................................................................................................................. 7

10.3 Measurement of perchlorate ....................................................................................................................................................... 7

10.4 Validity check of the calibration function ........................................................................................................................ 8

11 Calculation .................................................................................................................................................................................................................. 8

12 Expression of results ........................................................................................................................................................................................ 8

13 Test report ................................................................................................................................................................................................................... 8

Annex A (normative) Elimination of dissolved sulfate, chloride, hydrogen carbonate,

carbonate and metals ...................................................................................................................................................................................... 9

Annex B (normative) Determination of perchlorate using inline matrix elimination and

applying re-injection analysis ..............................................................................................................................................................14

Annex C (normative) Determination of perchlorate using inline matrix elimination and

concentration applying two-dimensional ion chromatography (2DIC) ...................................................18

Annex D (informative) Performance data ....................................................................................................................................................22

Bibliography .............................................................................................................................................................................................................................25

© ISO 2017 – All rights reserved iii
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SIST EN ISO 19340:2018
ISO 19340:2017(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

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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 147, Water quality, Subcommittee SC 2,

Physical, chemical and biochemical methods.
iv © ISO 2017 – All rights reserved
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SIST EN ISO 19340:2018
INTERNATIONAL STANDARD ISO 19340:2017(E)
Water quality — Determination of dissolved perchlorate —
Method using ion chromatography (IC)

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 and to

determine the applicability of any other restrictions.

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 dissolved perchlorate in water (e.g. drinking

water, mineral water, raw water, surface water, partially treated water or swimming pool water, waste

water from drinking/swimming pool water treatment plants).

Appropriate pre-treatment of the sample (e.g. matrix elimination) allows a direct determination of

perchlorate ≥ 1 µg/l.

The working range is restricted by the ion-exchange capacity of the separator column. Dilution of the

sample to the working range can be necessary.
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 3696, Water for analytical laboratory use — Specification and test methods

ISO 8466-1, Water quality — Calibration and evaluation of analytical methods and estimation of

performance characteristics — Part 1: Statistical evaluation of the 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
No terms and definitions are listed in this document.

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 Interferences

Perchlorate is known to be susceptible to microbiological degradation in the absence of nitrate and by

anaerobic bacteria (References [5] and [6]).
© ISO 2017 – All rights reserved 1
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SIST EN ISO 19340:2018
ISO 19340:2017(E)

Any substance that has a retention time coinciding with perchlorate and producing a detector response

can interfere. Co-elution can be solved by changing separator columns, eluent strength (e.g. gradient

elution), modifying the eluent with organic solvents or by selective removal of the interference by

sample pre-treatment.

Higher chloride, sulfate, nitrate, orthophosphate, hydrogen carbonate and carbonate concentrations

(e.g. 1 g/l) can interfere with the determination of perchlorate (co-elution) or can have an impact on

the retention time or the peak shape (distortion) or recovery of perchlorate. This effect can be checked

for every matrix by standard addition and the recovery of perchlorate should be within 85 % to 115 %.

Interferences can be reduced by sample dilution or with the aid of special cation exchangers (see 7.2

and Clause 9) or be resolved by the application of advanced inline cutting or re-injection techniques

(see Annexes A, B and C).

Metals like iron or aluminium present in samples and eluent will bind to the resin material of the

separator column or suppressor resulting in a loss of performance. Metal ions can be eliminated with

the aid of special cation exchangers (see Annex A and Clause 9).

Solid particles and organic compounds (such as mineral oils, detergents and humic acids) shorten the

lifetime of the pre-column and the separator column (see Clause 9).
5 Principle

The method requires the application of high-capacity separator columns which allow the injection of

sample volumes, e.g. up to 4 ml.

If necessary, the sample is pre-treated in order to remove anions, metals, organics and solids (see

Clause 9).

Measurement of perchlorate is performed with or without matrix elimination and with or without pre-

concentration (see 10.3 and Annexes A, B and C).

Perchlorate is separated by ion chromatography (IC) with suppressed conductivity detection (CD).

As stationary phase, an anion exchange resin is used. Aqueous solutions of salts of monobasic acids and

dibasic acids are used as eluents for isocratic or gradient elution e.g. carbonate-, hydrogen carbonate-,

hydroxide-eluent and an organic modifier like acetone or acetonitrile (6.3).

Resolution, R, shall be checked to ensure that it complies with the required separation conditions (8.1).

The concentration of perchlorate is determined after a calibration according to ISO 8466-1 or

ISO 8466-2.

Control experiments are necessary to check the validity of the calibration function. Replicate

determinations can be necessary. The method of standard addition can be applied if matrix interferences

are expected.
6 Reagents

Use only reagents of pro analysis grade free of compounds containing perchlorate. Weigh the

reagents with an accuracy of ±1 % of the nominal mass, unless stated otherwise. Prepare alternative

concentrations or volumes of solutions as described in 6.3 to 6.5, if necessary. Alternatively, use

commercially available solutions of the required concentration.
6.1 Water, ISO 3696, grade 1 and with a resistivity of ≥ 18,2 MΩ cm (25 °C).
6.2 Sodium perchlorate, NaClO , > 99 %.
2 © ISO 2017 – All rights reserved
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SIST EN ISO 19340:2018
ISO 19340:2017(E)
6.3 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 an organic modifier, 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 8.1. Use eluents as long as the requirements in Clause 8 and in 10.3

are met.
An example for an appropriate eluent manually prepared is given in 6.3.2.
6.3.1 Sodium hydroxide solution, w(NaOH) = 50 %.
6.3.2 Sodium hydroxide eluent, ρ(NaOH) = 0,05 mol/l.

Dissolve 4 g of sodium hydroxide solution (6.3.1) in approximately 900 ml of water (6.1) in a 1 000 ml

volumetric flask and dilute to volume with water (6.1). Mix and degas, e.g. by sparging with helium for

approximately 10 min. Store the eluent in a glass or polyethene eluent reservoir under an inert helium

atmosphere to minimize carbonate contamination. Prepare the eluent on the day of use.

NOTE Solutions of manually prepared sodium hydroxide can be susceptible to carbonate contamination

resulting from adsorption of carbon dioxide from the atmosphere. This contamination can lead to irreproducible

perchlorate retention times, elevated instrument background conductivity and increased baseline noise/drift.

6.4 Perchlorate standard solution.

Depending on the concentrations expected, prepare the following standard solutions of different

perchlorate concentrations from the stock solution (6.4.1). Note the possible risk of changes in

concentration caused by interaction with the vessel material which will increase with decreasing

perchlorate concentration. Store the standard solutions in polyethene or glass bottles.

6.4.1 Perchlorate stock solution, ρ ClO = 1 000 mg/l.

Dry approximately 1,5 g sodium perchlorate (6.2) at (110 ± 5) °C for 2 h. Dissolve (1,231 ± 0,001) g of

the dried sodium perchlorate in approximately 800 ml of water (6.1) in a 1 000 ml volumetric flask and

dilute to volume with water (6.1).

Store the solution at 2 °C to 8 °C in polyethene or glass bottles. The solution is stable for 12 months.

6.4.2 Perchlorate standard solution I, ρ ClO = 100 mg/l.

Pipette 10,0 ml of sodium perchlorate stock solution (6.4.1) into a 100 ml volumetric flask and dilute to

volume with water (6.1).

Store the solution at 2 °C to 8 °C in polyethene or glass bottles. The solution is stable for six months.

6.4.3 Perchlorate standard solution II, ρ ClO = 1 mg/l.

Pipette 1,0 ml of standard solution I (6.4.2) into a 100 ml volumetric flask, dilute to volume with

water (6.1).

Store the solution at 2 °C to 8 °C in polyethene or glass bottles. The solution is stable for three months.

© ISO 2017 – All rights reserved 3
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SIST EN ISO 19340:2018
ISO 19340:2017(E)
6.5 Perchlorate calibration solutions

Depending on the perchlorate concentration expected in the sample, use the perchlorate standard

solutions I or II (6.4.2 or 6.4.3) to prepare 5 to 10 calibration solutions distributed over the expected

working range as evenly as possible.

For example, proceed as follows for the range 1 µg/l to 5,5 µg/l perchlorate. Pipette into a series of

100 ml volumetric flasks the volumes described in Table 1.
Table 1 — Example for the preparation of calibration solutions
Volume standard
100 µl 150 µl 200 µl 250 µl 300 µl 350 µl 400 µl 450 µl 500 µl 550 µl
solution II (6.4.3)
ρ ClO (µg/l) 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5
( )
Prepare the calibration solutions on the day of use.
6.6 Blank solution
Fill a volumetric flask (e.g. 100 ml) with water (6.1).
7 Apparatus
The usual laboratory apparatus and, in particular, the following.

7.1 Ion chromatographic system, complying with the quality requirements given in Clause 8, i.e.

resolution. In general, it shall consist of the following components (see Figure 1).

7.1.1 Separator column, with the specified separating performance (8.1).
7.1.2 Precolumn, if necessary (see Clause 4).

NOTE The use of a precolumn is advantageous not only for the analyses of waters highly loaded with organics

(see Clause 4). It serves as well to protect the separator column. In general, two different types of precolumns are

available: those containing the same or similar resin material as the separator column, and those packed with a

non-functionalised resin.
7.1.3 Conductivity detector (CD), with a suppressor device.
7.1.4 Eluent reservoir and a degassing unit.
7.1.5 IC-pump, suitable for isocratic or gradient technique, respectively.

7.1.6 Sample delivery device, e.g. sample pump, including a sample injection system incorporating a

sample loop of appropriate volume (e.g. 1 ml to 4 ml) or an autosampler device.

7.1.7 Recording device, e.g. PC with software for chromatography data acquisition and evaluation.

7.2 SPE-cartridges.

7.2.1 Cation exchanger in the Na-form, optional: metal clean up column for inline use.

4 © ISO 2017 – All rights reserved
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SIST EN ISO 19340:2018
ISO 19340:2017(E)

7.2.2 Cartridges, with non-polar phases to be used for sample preparation (e.g. polyvinylpyrrolidone,

RP C18).
Optional.
Figure 1 — Schematic representation of an ion chromatographic system
8 Quality requirements
8.1 Performance of the separator column

In chromatograms of samples and standard solutions, the peak resolution, R, between the anion

of interest and its nearest peak shall not fall below 1,3 (see Formula (1) and Figure 2). Separation

conditions shall be such that possible interfering anions will not interfere with the anion of interest.

If R fails the criteria ≥ 1,3 or perchlorate elutes as a rider peak (see Figure A.1) due to higher

concentrations of matrix ions (e.g. chloride, sulfate, nitrate and carbonate), then if necessary,

— dilute the sample,
— change separator columns,
— change the eluent strength (e.g. gradient elution),
— modify the eluent with organic solvents,
— remove the interference selectively by sample pre-treatment (Annex A), and/or

— apply column cut or re-injection techniques according to Annex B or Annex C, and

— determine recovery or apply standard addition.
© ISO 2017 – All rights reserved 5
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SIST EN ISO 19340:2018
ISO 19340:2017(E)
Key
w width of peak 1
w width of peak 2
t retention time, in seconds
y signal
1 peak 1
2 peak 2

Figure 2 — Graphical representation of the parameters to calculate the peak resolution, R

NOTE 1 Within the scope of this document, the calculation of resolution, R, is appropriate for both isocratic

and gradient elution.
Calculate the peak resolution R for the peak pair 2,1 using Formula (1):
2,1
2×−()tt
RR21
R = (1)
21,
ww+
where
t is the retention time, in seconds, of the first peak;
t is the retention time, in seconds, of the second peak;
w is the peak width, in seconds, on the time axis of the first peak;
w is the peak width, in seconds, on the time axis of the second peak.

NOTE 2 w , w being the base width of the constructed isosceles triangle over each Gaussian peak.

1 2
8.2 Materials

All materials used shall not add a positive or negative bias to the perchlorate result.

9 Sampling and sample pre-treatment
Use clean vessels (e.g. glass, polyethene, polypropene, PTFE) for sampling.
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SIST EN ISO 19340:2018
ISO 19340:2017(E)

Perchlorate is known to be susceptible to microbiological degradation in absence of nitrate and by

anaerobic bacteria (see References [5] and [6]). If necessary, reduce these risks by filtering the sample

using a 0,2 µm membrane filter at the sampling site. Store the sample with headspace to reduce the

potential for degradation by any remaining organisms (see References [5] and [6]). Cooling the sample

during transportation is advisable.

If necessary, eliminate metals with the aid of cation exchangers (e.g. SPE-cartridge in the Na-form).

If necessary, remove solids with the aid of a membrane filter of pore size 0,45 μm.

NOTE Hydrophilic polypropylene or polyethersulfonate filters can be applied as they have been

proved acceptable. The use of a polyvinylidene fluoride (PVDF) filter can cause total loss of perchlorate (see

Reference [7]). If necessary, remove organic compounds and solids with the aid of a non-polar adsorbent (e.g.

SPE-cartridge, column) or dialysis.
Analyse the sample within 28 d after sampling.
10 Procedure
10.1 General

Set up the ion chromatographic system (7.1) in accordance with the instrument manufacturer’s

instructions.
Run the eluent. Once the baseline is stable, analysis can begin.

Perform the calibration as given in 10.2. Measure the samples and blank solution (6.6) according to 10.3.

10.2 Calibration

Inject the perchlorate calibration solutions (6.5). The measured signal (peak area or peak height) is

proportional to the perchlorate concentration.

When the analytical system is first started up and at intervals afterwards, establish a calibration

function (see ISO 8466-1 or ISO 8466-2).

Use the data obtained (peak area or peak height) to calculate the regression line as specified in

ISO 8466-1 or ISO 8466-2.

Subsequently, verify the continuing validity of the established calibration function (10.4).

NOTE Generally, the calibration method is not restricted to a calibration strategy covering a single

concentration decade as specified in ISO 8466-1 or ISO 8466-2 only. When calibrating over a larger range than

one concentration decade, a loss of accuracy, compared to that specified in ISO 8466-1 or ISO 8466-2, can occur.

10.3 Measurement of perchlorate

After establishing the calibration function, inject the sample into the chromatograph and measure the

peaks as described above. Prior to injection into the analyser, filter the sample through a membrane

filter (pore size according to the manufacturer’s instruction) to remove any particulate matter, if

...

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