EN ISO 14402:1999

SLOVENSKI STANDARD
01-december-2000
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Water quality - Determination of phenol index by flow analysis (FIA and CFA)(ISO
14402:1999)
Wasserbeschaffenheit - Bestimmung des Phenolindex mit der Fließanalytik (FIA und
CFA) (ISO 14402:1999)
Qualité de l'eau - Détermination de l'indice phénol par analyse en flux (FIA et CFA) (ISO
14402:1999)
Ta slovenski standard je istoveten z: EN ISO 14402:1999
ICS:
13.060.70 Preiskava bioloških lastnosti Examination of biological
vode properties of water
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 14402
First edition
1999-09-01
Water quality — Determination of phenol
index by flow analysis (FIA and CFA)
Qualité de l'eau — Détermination de l'indice phénol par analyse en flux (FIA
et CFA)
A
Reference number
ISO 14402:1999(E)
ISO 14402:1999(E)
Contents Page
1 Scope .1
2 Normative references .1
3 Determination of phenol index (without distillation) after extraction .1
3.1 Principle.1
3.2 Interferences .1
3.3 Reagents .2
3.4 Apparatus .4
3.5 Sampling.6
3.6 Procedure .7
3.7 Calculation of results .8
4 Determination of phenol index (without extraction) after distillation .9
4.1 Principle.9
4.2 Interferences .9
4.3 Reagents.9
4.4 Apparatus .10
4.5 Sampling.13
4.6 Procedure .13
4.7 Calculation of results .14
5 Expression of results .14
6 Precision and accuracy.14
7 Test report .14
Annex A (informative) Statistical data.15
Bibliography.17
©  ISO 1999
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 the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
ii
©
ISO
ISO 14402:1999(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.
International Standard ISO 14402 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee
SC 2, Physical, chemical biochemical methods.
Annex A of this International Standard is for information only.
iii
©
ISO
ISO 14402:1999(E)
Introduction
Methods for determination of water quality using flow analysis and automatic wet chemical procedures are par-
ticularly suitable for the processing of large sample series at a high analysis frequency.
Differentiation is needed between flow injection analysis (FIA) [1, 2] and continuous flow analysis (CFA) [3]. Both
methods include automatic dosage of the sample into a flow system (manifold) where the analytes in the sample
react with the reagent solutions on their way through the manifold. The sample preparation may be integrated in the
manifold. The reaction product is measured in a flow detector.
Phenol index is an analytical convention. It represents a group of aromatic compounds which under the specific
reaction conditions form coloured condensation products. The analytical result is expressed in terms of phenol
concentration.
This International Standard describes two methods: the determination of phenol index (without distillation) after
extraction, and the determination of phenol index (without extraction) after distillation.
It should be investigated whether and to what extent particular problems will require the specification of additional
marginal conditions.
iv
INTERNATIONAL STANDARD  © ISO ISO 14402:1999(E)
Water quality — Determination of phenol index by flow analysis
(FIA and CFA)
1 Scope
This International Standard specifies two methods for the determination of the phenol index in waters of different
origin (such as ground waters, surface waters, seep waters, and waste waters) in mass concentrations of 0,01 mg/l
to 1 mg/l (in the undiluted sample). In particular cases, the range of application may be adapted by varying the
operating conditions. Clause 3 describes the determination of phenol index (without distillation) after extraction, and
in clause 4 the determination of phenol index (without extraction) after distillation is given.
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 5667-3:1994, Water quality — Sampling — Part 3: Guidance on sample handling and preservation.
ISO 6439:1990, Water quality — Determination of phenol index — 4-Aminoantipyrine spectrometric methods after
distillation.
3 Determination of phenol index (without distillation) after extraction
3.1 Principle
The sample is fed into a continuously flowing carrier stream and mixed with also continuously flowing solutions of 4-
aminoantipyrine and potassium peroxodisulfate. Phenolic compounds in the sample are oxidized by potassium
peroxodisulfate, and the resulting quinones react with 4-aminoantipyrine, forming coloured condensation products.
These are extracted in a flow extraction unit from the aqueous phase into chloroform. The chloroform phase is
separated by a suitable phase separator (e.g. a hydrophobic semipermeable membrane), and the absorbance of
the organic phase is measured spectrometrically in a flow spectrometer at 470 nm to 475 nm. More information on
this analytical technique is given in the references [6 to 9].
It is absolutely essential that the test described in this International Standard be carried out by suitably qualified
staff.
3.2 Interferences
3.2.1 Chemical interferences
Under the prevailing reaction conditions, aromatic amines will also form condensation products with 4-aminoanti-
pyrine, leading to positive bias.
© ISO
ISO 14402:1999(E)
Interferences can occur when the sample, after the addition of the reagent solutions, does not reach a pH of
10,0 to 10,5. In particular this may occur in the cases of strongly acidic, strongly alkaline and buffered samples. In
these cases, the sample is adjusted to a pH between 5 and 7 prior to addition of the reagent solutions.
Further information on interferences is given in [5].
3.2.2 Physical interferences arising from applying CFA and FIA
If the samples contain particulate matter, refer to 3.5 (last paragraph). Turbid samples do not cause interferences
with the determination. In the event of coloured samples, check whether the colour can be extracted with
chloroform, and determine the sample blank without the addition of reagents R1 and R2. The difference in response
between the two measurements shall be taken into account with the evaluation (according to 3.7).
The interlaboratory trial (see clause 6 and annex A) has shown that detergents in waste water can strongly
influence the determination, because the foam produced in the flow system can disturb on the one hand the steam
distillation of volatile phenols (phenol index after distillation, see clause 4, and on the other hand the phase
segmentation and phase separation procedures (phenol index after extraction, see clause 3). In general such
interferences can easily be discovered.
In the case of significant detergent content, this International Standard is only applicable for phenol mass
concentrations above 0,1 mg/l.
3.3 Reagents
Use only reagents of recognized analytical grade quality. The reagent blank value shall regularly be checked (see
3.6.3). The solutions used for the flow system shall be degassed. If not stated otherwise, it is recommended to
degas the solutions under reduced pressure, because by this procedure the solutions are simultaneously purified.
WARNING — Phenol is toxic and can easily be absorbed through the skin. Chloroform is toxic and
cancerogenic. Waste containing these substances should be disposed of appropriately.
3.3.1  Water, of grade 1 in accordance with ISO 3696
3.3.2  Potassium hydroxide, KOH
3.3.3  Sodium hydrogencarbonate, NaHCO
3.3.4  4-aminoantipyrine (4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one), C H N O
11 13 3
3.3.5  Potassium peroxodisulfate, K S O
2 2 8
3.3.6  Phenol, C H OH
6 5
3.3.7  Boric acid, H BO
3 3
3.3.8  Ethanol, C H OH, 96 % mass fraction
2 5
3.3.9  2-Propanol, C H OH, 100 % mass fraction
3 7
3.3.10  Sulfuric acid, r(H SO ) = 1,84 g/ml
2 4
3.3.11  Hydrochloric acid
, HCl, 50 % mass fraction
3.3.12  Potassium hydroxide solution, c(KOH) = 1,0 mol/l
3.3.13  Buffer solution
Dissolve in a 1 000 ml graduated flask in approximately 500 ml of water (3.3.1): 23 g of sodium hydrogencarbonate
(3.3.3), 27 g of boric acid (3.3.7), and 35 g of potassium hydroxide (3.3.2) and make up to volume with water.
The pH of the buffer solution is approximately 10,3. The solution is stable for 1 month.
© ISO
ISO 14402:1999(E)
(symbol C in Figure 1)
3.3.14 Carrier solution
Use water (3.3.1) degassed under reduced pressure.
3.3.15  4-Aminoantipyrine solution I (symbol R1 in Figures 1 and 2)
Dissolve in a 100 ml graduated flask 0,5 g of 4-aminoantipyrine (3.3.4) in approximately 50 ml of buffer solution
(3.3.13), and make up to volume with buffer solution (3.3.13).
Degas the solution, e.g. by membrane filtration.
Prepare fresh solution every day.
3.3.16  Potassium peroxodisulfate solution (symbol R2 in Figures 1 and 2)
Dissolve in a 100 ml graduated flask 5 g of potassium peroxodisulfate (3.3.5) in approximately 90 ml of
...