EN ISO 16588:2003

Water quality - Determination of six complexing agents - Gas-chromatographic method (ISO 16588:2002)

This International Standard specifies a method for the determination of the following six water-soluble organic complexing agents in the concentration range from 0,5 micrograms/litre to 200 micrograms/litre:
EDTA (ethylenedinitrilotetraacetic acid);NTA (nitrilotriacetic acid);DTPA (diethylenetrinitrilopentaacetic acid);MGDA (methylglycinediacetic acid);ß-ADA (ß-alaninediacetic acid);1,3-PDTA (1,3-propylenedinitrilotetraacetic acid).
The method is applicable to drinking, ground, surface and waste water.

Wasserbeschaffenheit - Bestimmung von sechs Komplexbildnern - Gaschromatographisches Verfahren (ISO 16588:2002)

Diese Internationale Norm legt ein Verfahren zur Bestimmung der in der Tabelle 1 genannten löslichen organischen Komplexbildner fest. Das Verfahren ist geeignet für einen Konzentrationsbereich von 0,5 µg/l bis 200 µg/l und einem Probenvolumen zwischen 50 ml und 100 ml. Bei Verdünnung ändert sich der Konzentrationsbereich. Das Verfahren ist anwendbar auf Trinkwasser, Grund-, Oberflächen- und Abwasser.
Tabelle 1 - Nach diesem Verfahren bestimmbare Komplexbildner
Nr   Name   Zusammensetzung   Molare Masse g/mol   CAS-Nr a  
1   EDTA - Ethylendinitrilotetraessigsäure   C10H16O8N2   292,25   60-00-4
2   NTA - Nitrilotriessigsäure   C6H9O6N   191,14   139-13-9
3   DTPA - Diethylentrinitrilopentaessigsäure   C14H23O10N3   393,35   67-43-6
4   MGDA - Methylenglycindiessigsäure   C7H11O6N   205,17   29578-05-0
5   ß-ADA - ß-Alanindiessigsäure   C7H11O6N   205,17   6245-75-6
6   1,3-PDTA - 1,3-Propylendinitrilotetraessigsäure   C11H18O8N2   306,27   1939-36-2
a   CAS: Chemical Abstracts System
Für Abwasser ist zur Verminderung von Matrixeinflüssen ein geringeres Probenvolumen, z. B. 5 ml oder 10 ml, vorteilhaft.
Die Adsorption der sechs Komplexbildner an Feststoffe ist vernachlässigbar klein.
Nach diesem Verfahren sind auch weiteres Komplexbildner ähnlicher Zusammensetzung bestimmbar, vorausgesetzt, sie verhalten sich bei der Probenvorbereitung, Derivatisierung und Gaschromatographie gleichartig. Dies muss im Einzelfall geprüft werden.

Qualité de l'eau - Dosage des agents complexants - Méthode par chromatographie en phase gazeuse (ISO 16588:2002)

L'ISO 16588:2002 spécifie une méthode pour le dosage de six agents complexants organiques solubles dans l'eau, dans la gamme de concentrations allant de 0,5 microgrammes/litre à 200 microgrammes/litre. Ces six agents complexants sont les suivants:
EDTA (acide éthylènedinitrilotétraacétique);NTA (acide nitrilotriacétique);DTPA (acide diéthylènetrinitrilopentaacétique);MGDA (acide méthylglycinediacétique);bêta-ADA (acide bêta-alaninediacétique);1,3-PDTA (acide 1,3-propylènedinitrilotétraacétique).
La méthode est applicable à l'eau potable, aux eaux souterraines, aux eaux de surface et aux eaux usées.

Kakovost vode – Določevanje šestih kompleksirajočih agensov – Metoda plinske kromatografije (ISO 16588:2002)

General Information

• Status: Published
• Publication Date: 25-Nov-2003
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: CEN/TC 230 - Water analysis
• Drafting Committee: CEN/TC 230/WG 1 - Physical and biochemical methods
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 21-May-2008
• Completion Date: 21-May-2008
• Directive: 2000/60/EC - Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy (substitutes Directive Reference 01/991 - Common Position on WFD)
• Ref Project: SIST EN ISO 16588:2004 - Water quality - Determination of six complexing agents - Gas-chromatographic method (ISO 16588:2002)

Relations

• Amended By: EN ISO 16588:2003/A1:2005 - Water quality - Determination of six complexing agents - Gas-chromatographic method (ISO 16588:2002/Amd 1:2004)
• Effective Date: 22-Dec-2008

Overview

EN ISO 16588:2003 / ISO 16588:2002 defines a validated gas‑chromatographic method for the determination of six water‑soluble organic complexing agents in natural and treated waters. The method covers EDTA, NTA, DTPA, MGDA, β‑ADA and 1,3‑PDTA in the concentration range 0.5 µg/L to 200 µg/L (typical sample volume 50–100 mL) and is applicable to drinking, ground, surface and waste water. The standard describes sample stabilization, derivatization (esterification), extraction, chromatographic separation and quantitative determination by a nitrogen‑sensitive detector or mass spectrometry (GC or GC‑MS).

Key topics and requirements

• Analytes covered: EDTA, NTA, DTPA, MGDA, β‑ADA, 1,3‑PDTA (other similar complexing agents may be included after validation).
• Concentration range: 0.5–200 µg/L (adjustable by sample volume/dilution).
• Sample types: Drinking, ground, surface and waste water (smaller sample volumes recommended for wastewater, e.g. 5–10 mL, to reduce matrix effects).
• Principle: Stabilize sample (formaldehyde), evaporate, acidify and evaporate, esterify to n‑propyl/iso‑propyl/n‑butyl esters, extract with n‑hexane, separate by GC and quantify by nitrogen‑sensitive detector or MS.
• Standards & controls: Use internal standard (1,2‑PDTA for some analytes) and control standards such as heptadecane/octadecanenitrile or 1‑chlorotetradecane for GC/GC‑MS steps.
• Interferences and limitations: Bismuth complexes may resist breakdown (losses possible >100 µg/L); high salt (>2 g/L NaCl) hinders complete evaporation; high calcium (>200 mg/L Ca2+) can cause EDTA losses. Adsorption to solids is negligible.
• Reagents & equipment: Requires high‑purity deionized water, esterification reagent (alcohol + acetyl chloride), formaldehyde stabilization, n‑hexane extraction, GC/GC‑MS and nitrogen‑sensitive detectors; specialist glassware and qualified laboratory personnel are essential.
• Quality control: Calibration with stock and intermediate standards; documentation of sample handling, stabilization and analytical conditions.

Applications and users

EN ISO 16588 is intended for:

• Environmental and public‑health water quality monitoring.
• Drinking water compliance testing and surveillance.
• Wastewater and industrial effluent monitoring to detect chelating agent discharges.
• Analytical and research laboratories performing GC/GC‑MS water analysis.
• Regulatory bodies and consultants specifying reliable methods for chelator quantification.

Keywords: EN ISO 16588, ISO 16588, water quality standard, complexing agents, EDTA analysis, GC‑MS, gas chromatography, NTA, DTPA, MGDA, β‑ADA, 1,3‑PDTA.

Related standards

• ISO 3696 - Water for analytical laboratory use (purity requirements)
• ISO 5667‑1 / ISO 5667‑2 - Sampling guidance and techniques for water quality investigations

For laboratories, implementing EN ISO 16588 ensures traceable, standardized measurement of key chelating agents in diverse water matrices using GC or GC‑MS workflows.

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2004
.DNRYRVWYRGH±'RORþHYDQMHãHVWLKNRPSOHNVLUDMRþLKDJHQVRY±0HWRGDSOLQVNH
NURPDWRJUDILMH,62
Water quality - Determination of six complexing agents - Gas-chromatographic method
(ISO 16588:2002)
Wasserbeschaffenheit - Bestimmung von sechs Komplexbildnern -
Gaschromatographisches Verfahren (ISO 16588:2002)
Qualité de l'eau - Dosage des agents complexants - Méthode par chromatographie en
phase gazeuse (ISO 16588:2002)
Ta slovenski standard je istoveten z: EN ISO 16588:2003
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 16588
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2003
ICS 13.060.50
English version
Water quality - Determination of six complexing agents - Gas-
chromatographic method (ISO 16588:2002)
Qualité de l'eau - Dosage des agents complexants - Wasserbeschaffenheit - Bestimmung von sechs
Méthode par chromatographie en phase gazeuse (ISO Komplexbildnern - Gaschromatographisches Verfahren
16588:2002) (ISO 16588:2002)
This European Standard was approved by CEN on 3 November 2003.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16588:2003 E
worldwide for CEN national Members.

Foreword
The text of ISO 16588:2002 has been prepared by Technical Committee ISO/TC 147 "Water
quality” of the International Organization for Standardization (ISO) and has been taken over as
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 May 2004, and conflicting national standards
shall be withdrawn at the latest by May 2004.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
Endorsement notice
The text of ISO 16588:2002 has been approved by CEN as EN ISO 16588:2003 without any
modifications.
NOTE Normative references to International Standards are listed in Annex ZA (normative).
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of
any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
NOTE Where an International Publication has been modified by common modifications, indicated
by (mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 3696 1987 Water for analytical laboratory use - EN ISO 3696 1995
Specification and test methods
ISO 5667-1 1980 Water quality - Sampling - Part 1: EN 25667-1 1993
Guidance on the design of sampling
programmes
ISO 5667-2 1991 Water quality - Sampling - Part 2: EN 25667-2 1993
Guidance on sampling techniques
INTERNATIONAL ISO
STANDARD 16588
First edition
2002-11-01
Water quality — Determination of six
complexing agents — Gas-chromatographic
method
Qualité de l'eau — Dosage de six agents complexants — Méthode par
chromatographie en phase gazeuse

Reference number
ISO 16588:2002(E)
ISO 16588:2002(E)
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ii ISO 2002 – All rights reserved

ISO 16588:2002(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Principle . 2
4 Interferences . 2
5 Reagents . 2
6 Apparatus . 4
7 Sampling and sample stabilization . 4
8 Procedure . 5
9 Calibration . 7
10 Expression of results . 9
11 Test report . 9
Annex
A Examples of columns, chromatograms and mass spectra. 10
Bibliography. 12
©
ISO 2002 – All rights reserved iii

ISO 16588:2002(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 16588 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee
SC 2, Physical, chemical and biochemical methods.
Annex A of this International Standard is for information only.
©
iv ISO 2002 – All rights reserved

ISO 16588:2002(E)
Introduction
It is essential that the test described in this International Standard be carried out by suitably qualified staff.
It should be investigated whether and to what extent particular problems will require the specification of additional
conditions.
©
ISO 2002 – All rights reserved v

INTERNATIONAL STANDARD ISO 16588:2002(E)
Water quality — Determination of six complexing agents —
Gas-chromatographic method
WARNING — Persons using this International Standard should be familiar with normal laboratory practice.
This standard 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 ensure compliance with
any national regulatory conditions.
1 Scope
This International Standard specifies a method for the determination of the water-soluble organic complexing agents
listed in Table 1 in the concentration range from 0,5µg/l to 200µg/l, if a sample volume between 50 ml and 100 ml is
used. The concentration range may change if diluted solutions are analysed. The method is applicable to drinking,
ground, surface and waste water.
Table 1 — Complexing agents determinable by this method
a
No. Name Composition Molecular mass CAS number
1EDTA — ethylenedinitrilotetraacetic acid C H O N 292,25 60-00-4
10 16 8 2
2NTA — nitrilotriacetic acid C H O N 191,14 139-13-9
6 9 6
3DTPA — diethylenetrinitrilopentaacetic acid C H O N 393,35 67-43-6
14 23 10 3
4MGDA — methylglycinediacetic acid C H O N 205,17 29578-05-0
7 11 6
5ββ-ADA — -alaninediacetic acid C H O N 205,17 6245-75-6
7 11 6
61,3-PDTA — 1,3-propylenedinitrilotetraacetic acid C H O N 306,27 1939-36-2
11 18 8 2
a
CAS: Chemical Abstracts System
In waste water analysis, it is recommended that a smaller sample volume, e.g. 5ml or 10ml, be used in order to
reduce matrix effects.
The adsorption of the six complexing agents on solid materials is negligibly low.
Other complexing agents of similar composition may also be determined using this method, provided they behave
similarly during sample pretreatment, derivatization and gas chromatography. This shall be checked in each
individual case.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 5667-1:1980, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes
ISO 5667-2:1991, Water quality — Sampling — Part 2: Guidance on sampling techniques
©
ISO 2002 – All rights reserved 1

ISO 16588:2002(E)
3Principle
A test sample is stabilized with formaldehyde and evaporated to dryness. Hydrochloric or formic acid is added and
the sample again evaporated to dryness. The complexing agents are then esterified to the n-propyl, iso-propyl or
n-butyl esters. Water is added and the esters are extracted with n-hexane, separated and identified by gas
chromatography, and determined quantitatively with a nitrogen-sensitive detector or by mass spectrometry.
For the determination of EDTA, DTPA, and 1,3-PDTA, 1,2-propylenedinitrotetraacetic acid (1,2-PDTA) is used as an
internal standard through the whole procedure. When a nitrogen-sensitive detector is used, heptadecane- and/or
octadecanenitrile is used as a control standard in the gas-chromatographic step. 1-Chorotetradecane may be used
as the control standard if detection by mass spectrometry is chosen.
Alternatively, C-labelled standards may be used.
4 Interferences
In spite of their stability, complexes of these complexing agents with heavy metals are broken up and the complexing
agents determined, except in the case of bismuth. With samples containing bismuth in concentrations > 100µg/l,
losses can be expected.
In the case of high salt concentrations (> 2 g/l of NaCl, corresponding to an electrical conductivity of about
400 mS/m), complete evaporation to dryness may be difficult. The complete removal of water is necessary, however,
for the subsequent esterification. Therefore, samples have to be diluted or smaller sample volumes have to be taken.
2+
In the presence of calcium ions in concentrations exceeding 200 mg/l of Ca , losses of EDTA will occur.
5Reagents
All reagents shall be free from impurities which could interfere with the reactions. Throughout the procedure, use only
deionized water (5.1).
5.1 Deionized water, grade 1 as specified in ISO 3696.
5.2 Gases for gas chromatography and mass spectrometry, as specified by the instrument manufacturers.
5.3 Nitrogen, of purity � 99,996 %.
5.4 n-Propanol or iso-propanol or n-butanol for the preparation of esterification reagent (5.6).
5.5 Acetyl chloride.
5.6 Esterification reagent.
Cautiously mix by swirling in a 400 ml beaker 90 ml of n-propanol or iso-propanol or n-butanol (5.4) with 10 ml of
acetyl chloride (5.5).
CAUTION — Considerable heat is evolved.
The mixture is stable for at least 1 month if stored at room temperature.
5.7 Reference compounds.
5.7.1 Nitrilotriacetic acid (NTA), C H O N, of purity � 99 %.
6 9 6
5.7.2 Ethylenedinitrilotetraacetic acid (EDTA), C H O N , of purity � 99 %.
10 16 8 2
5.7.3 Diethylenetrinitrilopentaacetic acid (DTPA), C H O N , of purity � 99 %.
14 23 10 3
©
2 ISO 2002 – All rights reserved

ISO 16588:2002(E)
5.7.4 Methylglycinediacetic acid (MGDA), C H O N.
7 11 6
5.7.5 ββββ-Alaninediacetic acid (ββββ-ADA), C H O N.
7 11 6
5.7.6 1,3-Propylenedinitrilotetraacetic acid (1,3-PDTA), C H O N , of purity � 99 %.
11 18 8 2
5.7.7 C-labelled reference compounds as listed in 5.7.1 to 5.7.6 (optional).
5.8 Control standards and internal standard.
5.8.1 Octadecanenitrile, C H N, of purity > 98 %.
18 35
5.8.2 Heptadecanenitrile, C H N, of purity > 98 %.
17 33
5.8.3 1-Chlorotetradecane, C H Cl, of purity > 98 %.
14 29
5.8.4 1,2-Propylenedinitrilotetraacetic acid (1,2-PDTA), C H O N , of purity > 98 %.
11 18 8 2
5.9 Formaldehyde, 37 % by volume aqueous solution.
5.10 n-Hexane.
5.11 Sodium sulfate, anhydrous.
5.12 Sodium hydroxide solution, .c(NaOH)= 1 mol/l
5.13 Hydrochloric acid, .c(HCl)= 5 mol/l
5.14 Hydrochloric acid, .c(HCl)= 1 mol/l
5.15 Formic acid, 50 % by volume aqueous solution.
5.16 Stock solutions for calibration purposes, .1 g/l
Prepare 1 g/l stock solutions as follows. Weigh 100 mg of each of the complexing agents 5.7.1 to 5.7.6 and 5.8.4 into
100 ml volumetric flasks, dissolve in 2 ml of sodium hydroxide solution (5.12
...