EN 25814:1992
(Main)Water quality - Determination of dissolved oxygen - Electrotechnical probe method (ISO 5814:1990)
Water quality - Determination of dissolved oxygen - Electrotechnical probe method (ISO 5814:1990)
Includes a procedure by means of an electrochemical cell which is isolated from the sample by a gas permeable membrane. Depending on the type of probe employed measurement can be made either as concentration of oxygen, percentage saturation or both. The procedure is suitable for measurements made in the field and for continuous monitoring and in the laboratory. It is the preferred procedure for highly coloured and turbid waters. It is suitable for natural, waste and saline waters.
Wasserbeschaffenheit - Bestimmung des gelösten Sauerstoffs - Elektrochemisches Verfahren (ISO 5814:1990)
Qualité de l'eau - Dosage de l'oxygène dissous - Méthode électrochimique à la sonde (ISO 5814:1990)
La présente Norme internationale prescrit une méthode électrochimique de dosage de l'oxygène dissous dans les eaux à l'aide d'une cellule électrochimique qui est isolée de l'échantillon par une membrane perméable aux gaz. Selon le type de sonde employé, le mesurage peut être fait soit en tant que concentration d'oxygène, en milligrammes par litre, soit en tant que taux de saturation (% d'oxygène dissous) ou les deux. La méthode mesure l'oxygène dans l'eau correspondant à un taux de saturation de 0 % à 100 %. Cependant, la plupart des appareils permettent des mesurages de valeurs supérieures à 100 %, c'est-à-dire une supersaturation. La méthode est utilisable pour les mesurages effectués sur le terrain et pour le contrôle permanent de l'oxygène dissous, ainsi que pour les dosages en laboratoire. C'est la méthode à préférer pour les eaux fortement colorées et troubles, ainsi que pour celles qui renferment des substances fixant le fer et l'iode, et susceptibles d'interférer avec la méthode iodométrique spécifiée dans l'ISO 5813. Les gaz et vapeurs, tels que le chlore, l'anhydride sulfureux, l'hydrogène sulfuré, les amines, l'ammoniac, l'anhydride carbonique, le brome et l'iode, éventuellement présents et diffusant à travers la membrane, peuvent fausser le résultat en influençant l'intensité de courant mesurée. D'autres substances présentes dans l'échantillon peuvent influencer l'intensité de courant mesurée en donnant lieu à un colmatage o 429u à une détérioration de la membrane, ou encore à une corrosion des électrodes ; les solvants, les huiles, les sulfures, les carbonates et les algues figurent parmi ces substances. La méthode est utilisable pour les eaux naturelles, résiduaires et 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 - Ugotavljanje raztopljenega kisika - Elektrokemijska metoda (ISO 5814:1990)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 25814:1996
01-oktober-1996
Kakovost vode - Ugotavljanje raztopljenega kisika - Elektrokemijska metoda (ISO
5814:1990)
Water quality - Determination of dissolved oxygen - Electrotechnical probe method (ISO
5814:1990)
Wasserbeschaffenheit - Bestimmung des gelösten Sauerstoffs - Elektrochemisches
Verfahren (ISO 5814:1990)
Qualité de l'eau - Dosage de l'oxygene dissous - Méthode électrochimique a la sonde
(ISO 5814:1990)
Ta slovenski standard je istoveten z: EN 25814:1992
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
SIST EN 25814:1996 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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ISO 5814:1990(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. Esch 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, govern-
mental and non-governmental, in liaison with ISO, also take patt in the
work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an Interna-
tional Standard requires approval by at least 75 % of the member bodies
casting a vote.
International Standard ISO 5814 was prepared by Technical Committee
ISO/TC 147, Water quality.
This second edition cancels and replaces the first edition (ISO
5814:1984), of which it constitutes a minor revision.
Annexes A and B of this International Standard are for information only.
8 ISO 1990
All rights reserved. No part of this publication may be reproduced or utilized in any form
or by any means, electronie or mechanical, including photocopylng and microfilm, without
Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzeriand
Printed in Switzerland
ii
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ISO 5814:1990(E)
INTERNATIONAL STANDARD
Determination of dissolved Oxygen -
Water quality -
Electrochemical probe method
cation, the edition indicated was valid. All Standards
1 Scope
are subject to revision, and Parties to agreements
based an this International Standard are encour-
This International Standard specifies an
aged to investigate the possibility of applying the
electrochemical method for the determination of
most recent edition of the Standard indicated below.
dissolved Oxygen in water by means of an
Members of IEC and ISO maintain registers of cur-
electrochemical cell which is isolated from the
rently valid International Standards.
Sample by a gas permeable membrane.
ISO 5813:1983, Water quality - Determination of dis-
Depending on the type of probe employed, meas-
solved Oxygen - lodometric method.
urement tan be made either as concentration of
Oxygen in milligrams per litre, percentage Saturation
(% dissolved Oxygen) or both. The method meas-
ures Oxygen in water corresponding to 0 % to
3 Princlple
100 % Saturation. However, most instruments per-
mit measurement of values higher than 100 % i.e. Immersion of a probe, consisting of a cell enclosed
Supersaturation.
by a selective membrane and containing the
electrolyte and two metallic electrodes, in the water
The method is suitable for measurements made in
to be analysed. (The membrane is practically
the field and for continuous monitoring of dissolved
impermeable to water and ionic dissolved matter,
Oxygen as well as measurements made in the labo-
but is permeable to Oxygen and a certain number
ratory. lt is the preferred method for highly coloured
of the other gases and lyophylic substances.)
and turbid waters, and also for waters containing
iron and iodine fixing substances, all of which may
Because of the potential differente between the
interfere in the iodometric method specified in electrodes, caused by galvanic action or an external
ISO 5813. Gases and vapours such as chlorine, sul- voltage, Oxygen passing through the membrane is
fur dioxide, hydrogen sulfide, amines, ammonia, reduced at the cathode, while metal ions pass into
carbon dioxide, bromine and iodine which diffuse Solution at the anode.
through the membrane, may interfere, if present, by
The current so produced is directly proportional to
affecting the measured current. Other substances
the rate of transport of Oxygen through the mem-
present in the Sample may interfere with the meas-
brane and the layer of electrolyte and hence to the
ured current by causing obstruc
...
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