SIST EN ISO 5814:2013
(Main)Water quality - Determination of dissolved oxygen - Electrochemical probe method (ISO 5814:2012)
Water quality - Determination of dissolved oxygen - Electrochemical probe method (ISO 5814:2012)
This International Standard specifies an electrochemical method for the determination of dissolved oxygen in water by means of an electrochemical cell which is isolated from the sample by a gas permeable membrane. Measurement can be made either as a concentration of oxygen in milligrams per litre, percentage saturation (% dissolved oxygen) or both. The method measures oxygen in water corresponding to 1 % to 100 % saturation. However, most instruments permit measurement of values higher than 100 %, i.e. supersaturation. The method measures oxygen in water with a saturation higher than 100 %, when special arrangements to prevent the outgassing of oxygen during the handling and measurement of the sample are made. The method is suitable for measurements made in the field and for continuous monitoring of dissolved oxygen, as well as measurements made in the laboratory. It is the preferred method for highly coloured and turbid waters, and also for analysis of waters not suitable for the Winkler titration method because of iron- and iodinefixing substances, which can interfere in the iodometric method specified in ISO 5813[1]. The method is suitable for drinking waters, natural waters, waste waters, and saline waters. If used for saline waters, such as sea or estuarine waters, a correction for salinity is essential.
Wasserbeschaffenheit - Bestimmung des gelösten Sauerstoffs - Elektrochemisches Verfahren (ISO 5814:2012)
Diese Internationale Norm beschreibt ein elektrochemisches Verfahren zur Bestimmung von gelöstem
Sauerstoff in Wasser mittels elektrochemischer Zelle, die von der Probe durch eine gasdurchlässige Membran
getrennt ist.
Das Messergebnis kann als Massenkonzentration in Milligramm je Liter (mg/l) gelöster Sauerstoff und/oder in
Prozent (%) relative Sauerstoffsättigung angegeben werden. Das Verfahren ist anwendbar zur Bestimmung
der relativen Sauerstoffsättigung im Bereich von 1 % bis 100 %. Mit den meisten Geräten lässt sich auch eine
relative Sauerstoffsättigung über 100 % (Übersättigung) bestimmen.
ANMERKUNG Eine Übersättigung ist möglich, wenn der Sauerstoffpartialdruck in der Wasserprobe höher ist als in der
atmosphärischen Luft. Besonders im Fall von starkem Algenwachstum ist eine Übersättigung von bis zu 200 % und mehr
möglich.
Bei einer relativen Sauerstoffsättigung von über 100 % ist die Bestimmung von Sauerstoff dann möglich,
wenn besondere Vorkehrungen während der Handhabung und der Messung der Probe getroffen werden, um
eine Ausgasung von Sauerstoff zu vermeiden.
Das Verfahren ist geeignet für die Messung des gelösten Sauerstoffs vor Ort, für kontinuierliche Messungen
und für Labormessungen. Das Verfahren kann auch bei stark gefärbten und trübstoffhaltigen Wässern
eingesetzt werden sowie bei Wässern, die iodbindende Stoffe enthalten und die sich somit nicht für die
titrimetrische Bestimmung nach Winkler eignen (Iodometrisches Verfahren nach ISO 5813).
Das Verfahren ist für Trink-, Grund-, Oberflächen- und Abwässer sowie für salzhaltige Wässer, wie Meer- und
Brackwasser, geeignet. Falls die Messung in salzhaltigen Wässern durchgeführt wird, ist eine Korrektur des
Messsignals in Abhängigkeit von der Salinität erforderlich.
Qualité de l'eau - Dosage de l'oxygène dissous - Méthode électrochimique à la sonde (ISO 5814:2012)
L'ISO 5814:2012 spécifie une méthode électrochimique de dosage de l'oxygène dissous dans l'eau à l'aide d'une cellule électrochimique qui est isolée de l'échantillon par une membrane perméable aux gaz.
Le mesurage peut être fait soit en tant que concentration en oxygène, en milligrammes par litre, soit en tant que pourcentage de saturation (% d'oxygène dissous) ou les deux. La méthode mesure l'oxygène dans l'eau correspondant à un taux de saturation de 1 % à 100 %. Cependant, la plupart des appareils permettent des mesurages de valeurs supérieures à 100 %, c'est-à-dire une sursaturation.
La méthode mesure l'oxygène dans l'eau avec une saturation supérieure à 100 %, lorsque des mesures spécifiques sont mises en ?uvre pour empêcher le dégazage de l'oxygène pendant la manipulation et le mesurage de l'échantillon.
La méthode est utilisable pour les mesurages effectués sur le terrain et pour le contrôle permanent de l'oxygène dissous, ainsi que pour les mesurages en laboratoire. C'est la méthode à préférer pour les eaux fortement colorées et troubles, ainsi que pour l'analyse des eaux inadaptées à la méthode de titrage de Winkler en raison des substances fixant le fer et l'iode susceptibles d'interférer avec la méthode iodométrique spécifiée dans l'ISO 5813.
La méthode est utilisable pour les eaux potables, les eaux naturelles, les eaux résiduaires et les eaux salines. Si elle est utilisée pour des eaux salines telles que les eaux de mers ou les eaux d'estuaires, une correction due à la salinité est essentielle.
Kakovost vode - Določevanje raztopljenega kisika - Elektrokemijska metoda (ISO 5814:2012)
Ta mednarodni standard opisuje elektrokemijsko metodo za določevanje raztopljenega kisika v vodi z elektrokemijsko celico, ki je od vzorca izolirana z membrano, ki prepušča pline. Meritev se lahko opravi kot koncentracija kisika v miligramih na liter, odstotek nasičenosti (% raztopljenega kisika) ali oboje. Metoda meri kisik v vodi, ki ustreza od 1 % do 100 % nasičenosti. Vendar večina instrumentov omogoča meritve vrednosti, višje od 100 %, tj. prenasičenost. Metoda meri kisik v vodi pri nasičenosti, višji od 100 %, kadar so uvedeni posebni ukrepi za preprečevanje samorazplinjenja kisika med ravnanjem z vzorcem in meritvami v zvezi z njim. Metoda je primerna za meritve na terenu in za neprestano spremljanje raztopljenega kisika ter tudi za meritve v laboratoriju. To je prednostna metoda za zelo obarvane in motne vode ter tudi za analizo vod, ki zaradi vsebnosti snovi, ki fiksirajo železo in jod ter lahko povzročajo motnje pri jodometrijski metodi iz standarda ISO 5813[1], niso primerne za titracijo po Winklerju. Metoda je primerna za pitne vode, naravne vode, odpadne vode in slane vode. Če se uporablja za slane vode, npr. za morske vode ali somornice, je potrebna korekcija za slanost.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 5814:2013
01-januar-2013
1DGRPHãþD
SIST EN 25814:1996
.DNRYRVWYRGH'RORþHYDQMHUD]WRSOMHQHJDNLVLND(OHNWURNHPLMVNDPHWRGD ,62
Water quality - Determination of dissolved oxygen - Electrochemical probe method (ISO
5814:2012)
Wasserbeschaffenheit - Bestimmung des gelösten Sauerstoffs - Elektrochemisches
Verfahren (ISO 5814:2012)
Qualité de l'eau - Dosage de l'oxygène dissous - Méthode électrochimique à la sonde
(ISO 5814:2012)
Ta slovenski standard je istoveten z: EN ISO 5814:2012
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
SIST EN ISO 5814:2013 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 5814:2013
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SIST EN ISO 5814:2013
EUROPEAN STANDARD
EN ISO 5814
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2012
ICS 13.060.50 Supersedes EN 25814:1992
English Version
Water quality - Determination of dissolved oxygen -
Electrochemical probe method (ISO 5814:2012)
Qualité de l'eau - Dosage de l'oxygène dissous - Méthode Wasserbeschaffenheit - Bestimmung des gelösten
électrochimique à la sonde (ISO 5814:2012) Sauerstoffs - Elektrochemisches Verfahren (ISO
5814:2012)
This European Standard was approved by CEN on 4 August 2012.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5814:2012: E
worldwide for CEN national Members.
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SIST EN ISO 5814:2013
EN ISO 5814:2012 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 5814:2013
EN ISO 5814:2012 (E)
Foreword
This document (EN ISO 5814:2012) 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 April 2013, and conflicting national standards shall be withdrawn at the
latest by April 2013.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 25814:1992.
According to the CEN/CENELEC Internal Regulations, the national standards organisations 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 5814:2012 has been approved by CEN as a EN ISO 5814:2012 without any modification.
3
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SIST EN ISO 5814:2013
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SIST EN ISO 5814:2013
INTERNATIONAL ISO
STANDARD 5814
Third edition
2012-10-15
Water quality — Determination of dissolved
oxygen — Electrochemical probe method
Qualité de l’eau — Dosage de l’oxygène dissous — Méthode
électrochimique à la sonde
Reference number
ISO 5814:2012(E)
©
ISO 2012
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SIST EN ISO 5814:2013
ISO 5814:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 5814:2013
ISO 5814:2012(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Interferences . 2
5 Reagents . 2
6 Apparatus . 2
7 Sampling and analysis procedure . 3
7.1 Sampling . 3
7.2 Measuring technique and precautions to be taken . 3
7.3 Calibration . 4
7.4 Determination . 4
8 Calculation and expression of results . 5
8.1 Dissolved oxygen concentration . 5
8.2 Dissolved oxygen expressed as percentage saturation . 5
9 Test report . 5
Annex A (informative) Physicochemical data for oxygen in water . 6
Annex B (informative) Performance data .12
Bibliography .14
© ISO 2012 – All rights reserved iii
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SIST EN ISO 5814:2013
ISO 5814:2012(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 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 5814 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
This third edition cancels and replaces the second edition (ISO 5814:1990), which has been technically revised.
The main changes compared to the second edition are:
a) a calibration procedure using water-saturated air is specified;
b) the calibration procedure using air-saturated water is omitted.
iv © ISO 2012 – All rights reserved
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SIST EN ISO 5814:2013
INTERNATIONAL STANDARD ISO 5814:2012(E)
Water quality — Determination of dissolved oxygen —
Electrochemical probe 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.
IMPORTANT — It is absolutely essential that tests conducted according to this International Standard
be carried out by suitably trained staff.
1 Scope
This International Standard specifies an electrochemical method for the determination of dissolved oxygen in
water by means of an electrochemical cell which is isolated from the sample by a gas permeable membrane.
Measurement can be made either as a concentration of oxygen in milligrams per litre, percentage saturation (%
dissolved oxygen) or both. The method measures oxygen in water corresponding to 1 % to 100 % saturation.
However, most instruments permit measurement of values higher than 100 %, i.e. supersaturation.
NOTE Supersaturation is possible when the partial pressure of oxygen is higher than in air. Especially when strong
algal growth is present, supersaturation of up to 200 % and above can occur.
The method measures oxygen in water with a saturation higher than 100 %, when special arrangements to
prevent the outgassing of oxygen during the handling and measurement of the sample are made.
The method is suitable for measurements made in the field and for continuous monitoring of dissolved oxygen,
as well as measurements made in the laboratory. It is the preferred method for highly coloured and turbid
waters, and also for analysis of waters not suitable for the Winkler titration method because of iron- and iodine-
[1]
fixing substances, which can interfere in the iodometric method specified in ISO 5813 .
The method is suitable for drinking waters, natural waters, waste waters, and saline waters. If used for saline
waters, such as sea or estuarine waters, a correction for salinity is essential.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable
for its application. 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
3 Principle
Immersion of a probe, consisting of a cell enclosed by a selective membrane and containing the electrolyte and
at least two metallic electrodes, in the water to be analysed.
NOTE The membrane is effectively impermeable to water and ionic dissolved matter, but is permeable to oxygen and
a certain number of other gases.
One of the electrodes is made of a noble metal like gold or platinum. Oxygen is reduced at its surface by
an electrochemical process. In order to make this process possible, a suitable electrochemical potential is
established at this electrode. For polarographic probes, this is achieved by applying an external voltage related
to a second electrode. Galvanic probes are able to build up the potential by themselves.
© ISO 2012 – All rights reserved 1
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SIST EN ISO 5814:2013
ISO 5814:2012(E)
The current resulting from the reduction of oxygen is directly proportional to the rate of transport of oxygen
through the membrane and the layer of electrolyte, and hence to the partial pressure of the oxygen in the
sample at a given temperature.
Temperature has two different influences. The first relates to the variation of gas permeability of the membrane
with temperature. So the primary signal of the probe has to be compensated with a built-in temperature sensor.
Meters manufactured recently are able to do this automatically. The second is the temperature effect on the
electrode reactions.
To calculate the percentage of saturation of samples in contact with an atmosphere, it is necessary to include
the effective pressure. This can be performed manually or by implementing a pressure sensor for automatic
compensation. Salinity can also be an influence.
4 Interferences
Gases and vapors such as chlorine, hydrogen sulfide, amines, ammonia, bromine, and iodine which diffuse
through the membrane can interfere, if present, by affecting the measured current.
Other substances present in the sample can interfere with the measured current by causing obstruction,
deterioration of the membrane or corrosion of the electrodes. These include solvents, oils, sulfides, carbonates,
and biofilms.
5 Reagents
During analysis, use only reagents of recognized analytical grade.
5.1 Water, grade 2, as specified in ISO 3696, optionally from commercial sources.
5.2 Sodium sulfite, anhydrous, Na SO or heptahydrate, Na SO ·7H O.
2 3 2 3 2
5.3 Cobalt(II) salt, for example cobalt(II) chloride hexahydrate, CoCl ·6H O.
2 2
5.4 Nitrogen gas, N , purity 99,995 % volume fraction or better.
2
6 Apparatus
6.1 Measuring instrument, comprising the components specified in 6.1.1 and 6.1.2.
6.1.1 Measuring probe, either of the galvanic type (e.g. lead/silver) or the polarographic type (e.g. silver/gold)
with, if required, a temperature-sensitive compensating device.
6.1.2 Meter, graduated to show the concentrations of dissolved oxygen directly, and/or percentage
saturation with oxygen.
6.2 Thermometer, graduated in at least 0,5 °C divisions.
NOTE Commonly a temperature sensor is integrated into the instrument (6.1).
6.3 Barometer, graduated to 1 hPa.
NOTE Usually the barometer is integrated into the instrument (6.1).
2 © ISO 2012 – All rights reserved
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SIST EN ISO 5814:2013
ISO 5814:2012(E)
7 Sampling and analysis procedure
7.1 Sampling
7.1.1 General
Samples should always be handled so that transfer of oxygen between water sample and air is inhibited.
As a matter of principle, the oxygen concentration shall be measured directly on site in the water body to be analysed.
If direct measurement in the water body is not possible, the measurement can also be taken in a gas-tight
connected flow-through device or immediately after sampling as a discrete sample.
Any discrete sampling procedure results in a higher measurement uncertainty.
While filling the sample vessel during sampling, oxygen uptake or oxygen stripping shall be minimized. Sample
transfer shall occur without any turbulence, i.e. by maintaining a laminar flow.
7.1.2 Dip-sampling (e.g. surface waters)
Take the sample by carefully and slowly dipping the sample vessel.
7.1.3 Sampling from taps
Connect an inert sampling tube, in a gas-tight fashion, to the tap and insert the sampling tube all the way down
to the bottom of the sampling vessel. Ensure that the volume of water allowed to overflow is at least three times
the capacity of the vessel.
7.1.4 Sampling with pumps
Only water-displacing submersible pumps should be used. Pumps that function according to the principle of
air displacement are not suitable. Fill the sample vessel from the bottom, using a sampling tube, and allow the
water to overflow. During sample transfer, the volume flow rate shall be controlled in order to guarantee a mainly
laminar flow. Ensure that the volume of water allowed to overflow is at least three times the capacity of the vessel.
7.2 Measuring technique and precautions to be taken
The measuring system shall be in a proper state as specified in the manufacturer’s instructions.
...
SLOVENSKI STANDARD
oSIST prEN ISO 5814:2010
01-julij-2010
.DNRYRVWYRGH'RORþHYDQMHUD]WRSOMHQHJDNLVLND(OHNWURNHPLMVNDPHWRGD
,62',6
Water quality - Determination of dissolved oxygen - Electrochemical probe method
(ISO/DIS 5814:2010)
Wasserbeschaffenheit - Bestimmung des gelösten Sauerstoffs - Elektrochemisches
Verfahren (ISO/DIS 5814:2010)
Qualité de l'eau - Dosage de l'oxygène dissous - Méthode électrochimique à la sonde
(ISO/DIS 5814:2010)
Ta slovenski standard je istoveten z: prEN ISO 5814
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
oSIST prEN ISO 5814:2010 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 5814:2010
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oSIST prEN ISO 5814:2010
EUROPEAN STANDARD
DRAFT
prEN ISO 5814
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2010
ICS 13.060.50 Will supersede EN 25814:1992
English Version
Water quality - Determination of dissolved oxygen -
Electrochemical probe method (ISO/DIS 5814:2010)
Qualité de l'eau - Dosage de l'oxygène dissous - Méthode Wasserbeschaffenheit - Bestimmung des gelösten
électrochimique à la sonde (ISO/DIS 5814:2010) Sauerstoffs - Elektrochemisches Verfahren (ISO/DIS
5814:2010)
This draft European Standard is submitted to CEN members for parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 230.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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 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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 5814:2010: E
worldwide for CEN national Members.
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oSIST prEN ISO 5814:2010
prEN ISO 5814:2010 (E)
Contents Page
Foreword .3
2
---------------------- Page: 4 ----------------------
oSIST prEN ISO 5814:2010
prEN ISO 5814:2010 (E)
Foreword
This document (prEN ISO 5814:2010) 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 document is currently submitted to the parallel Enquiry.
This document will supersede EN 25814:1992.
Endorsement notice
The text of ISO/DIS 5814:2010 has been approved by CEN as a prEN ISO 5814:2010 without any
modification.
3
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oSIST prEN ISO 5814:2010
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oSIST prEN ISO 5814:2010
DRAFT INTERNATIONAL STANDARD ISO/DIS 5814
ISO/TC 147/SC 2 Secretariat: DIN
Voting begins on: Voting terminates on:
2010-05-20 2010-10-20
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Water quality — Determination of dissolved oxygen —
Electrochemical probe method
Qualité de l'eau — Dosage de l'oxygène dissous — Méthode électrochimique à la sonde
[Revision of second edition (ISO 5814:1990)]
ICS 13.060.50
ISO/CEN PARALLEL PROCESSING
This draft has been developed within the International Organization for Standardization (ISO), and
processed under the ISO-lead mode of collaboration as defined in the Vienna Agreement.
This draft is hereby submitted to the ISO member bodies and to the CEN member bodies for a parallel
five-month enquiry.
Should this draft be accepted, a final draft, established on the basis of comments received, will be
submitted to a parallel two-month approval vote in ISO and formal vote in CEN.
In accordance with the provisions of Council Resolution 15/1993 this document is circulated in
the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué
en version anglaise seulement.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
©
International Organization for Standardization, 2010
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oSIST prEN ISO 5814:2010
ISO/DIS 5814
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oSIST prEN ISO 5814:2010
ISO/DIS 5814
Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Principle.2
4 Interferences .2
5 Reagents.2
6 Apparatus.2
7 Procedure.3
8 Calculation and expression of results .5
9 Test report.6
Annex A (informative) Physico-chemical data of oxygen in water .7
Bibliography.14
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oSIST prEN ISO 5814:2010
ISO/DIS 5814
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 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 5814 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
This third edition cancels and replaces the second edition (ISO 5814:1990), which has been technically
revised.
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oSIST prEN ISO 5814:2010
DRAFT INTERNATIONAL STANDARD ISO/DIS 5814
Water quality — Determination of dissolved oxygen —
Electrochemical probe 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.
IMPORTANT — It is absolutely essential that tests conducted according to this International Standard
be carried out by suitably trained staff.
1 Scope
This International Standard specifies an electrochemical method for the determination of dissolved oxygen in
water by means of an electrochemical cell which is isolated from the sample by a gas permeable membrane.
Measurement can be made either as a concentration of oxygen in milligrams per litre, percentage saturation
(% dissolved oxygen) or both. The method measures oxygen in water corresponding to 1 % to 100 %
saturation. However, most instruments permit measurement of values higher than 100 %, i.e. supersaturation.
NOTE Supersaturation is possible, when the partial pressure of oxygen is higher than in air. Especially in case of
strong algae growth supersaturation until 200 % and more is possible.
The method measures oxygen in water with a saturation higher than 100 %, when special arrangements to
prevent the outgassing of oxygen during the handling and measurement of the sample are made.
The method is suitable for measurements made in the field and for continuous monitoring of dissolved oxygen
as well as measurements made in the laboratory. It is the preferred method for highly coloured and turbid
waters, and also for analysis of waters not suitable for the Winkler titration method because of iron and iodine
fixing substances, which may interfere in the iodometric method specified in ISO 5813.
The method is suitable for drinking waters, natural waters, waste waters and saline waters. If used for saline
waters such as sea or estuarine waters, a correction for salinity is essential.
2 Normative references
The following referenced documents are indispensable for the application 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 5813, Water quality — Determination of dissolved oxygen — Iodometric method
ISO 7888, Water quality — Determination of electrical conductivity
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oSIST prEN ISO 5814:2010
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3 Principle
Immersion of a probe, consisting of a cell enclosed by a selective membrane and containing the electrolyte
and at least two metallic electrodes, in the water to be analysed.
NOTE The membrane is effectively impermeable to water and ionic dissolved matter, but is permeable to oxygen and
a certain number of other gases.
One of the electrodes is made of a noble metal like gold or platinum. Oxygen is reduced at its surface by an
electrochemical process. In order to make this process possible, a suitable electrochemical potential has to be
established at this electrode. For polarographic probes this is achieved by applying an external voltage related
to a second electrode. Galvanic probes are able to build up the potential by themselves.
The current resulting from the reduction of oxygen is directly proportional to the rate of transport of oxygen
through the membrane and the layer of electrolyte and hence to the partial pressure of the oxygen in the
sample at a given temperature.
Temperature has two different influences. The first influence relates to the variation of gas permeability of the
membrane with temperature. So the primary signal of the probe has to be compensated with a built in
temperature sensor. Meters at the state of the art are able to do this automatically. The second influence is
given by the sample and the temperature dependence of the solubility of oxygen in it.
For calculating the percentage of saturation of samples being in contact with an atmosphere, it is necessary to
include the effective pressure. This can be performed manually or by implementing a pressure sensor for
automatic compensation. Also salinity can be of influence.
4 Interferences
Gases and vapors such as chlorine, hydrogen sulfide, amines, ammonia, bromine and iodine which diffuse
through the membrane may interfere, if present, by affecting the measured current.
Other substances present in the sample may interfere with the measured current by causing obstruction, or
deterioration of the membrane or corrosion of the electrodes. These include solvents, oils, sulfides,
carbonates and biofilms.
5 Reagents
During analysis, use only reagents of recognised analytical grade.
5.1 Water, grade 2, as specified in ISO 3696.
5.2 Sodium sulfite, anhydrous, Na SO or heptahydrate, Na SO · 7 H O.
2 3 2 3 2
5.3 Cobalt(II) salt, for example cobalt(II)chloride hexahydrate, CoCl · 6 H O.
2 2
5.4 Nitrogen gas, N , Purity 99,995 % or better.
2
6 Apparatus
6.1 Measuring instrument, comprising the following components:
6.1.1 Measuring probe, either of the galvanic type (e.g. lead/silver) or the polarographic type (e.g.
silver/gold) with, if required a temperature-sensitive compensating device.
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oSIST prEN ISO 5814:2010
ISO/DIS 5814
6.1.2 Meter, graduated to show the concentrations of dissolved oxygen directly, and/or percentage
saturation with oxygen.
6.2 Thermometer, graduated to at least 0,5 °C.
NOTE Commonly a temperature sensor is integrated into the instrument.
6.3 Barometer, graduated to 1 hPa.
NOTE Usually the barometer is integrated into the instrument.
7 Procedure
7.1 Sampling
As a matter of principle, the oxygen concentration shall be measured directly on site in the water body to be
analysed.
If direct measuring in the water body is not possible, the measuring can also take place in a gastight
connected flow-through device or immediately after sampling as a discrete sample.
Any discrete sampling procedure will result in a higher measurement uncertainty.
Whilst filling the sample vessel during sampling, oxygen uptake or oxyg
...
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