oSIST prEN ISO 15923-1:2024

SLOVENSKI STANDARD
01-maj-2024
Kakovost vode - Določanje izbranih parametrov s sistemi diskretne analize - 1. del:
amoniak, nitrat, nitrit, klorid, ortofosfat, sulfat in silikat s fotometrijsko detekcijo
(ISO 15923-1:2013)
Water quality - Determination of selected parameters by discrete analysis systems - Part
1: Ammonium, nitrate, nitrite, chloride, orthophosphate, sulfate and silicate with
photometric detection (ISO 15923-1:2013)
Wasserbeschaffenheit - Bestimmung von ausgewählten Parametern mittels
Einzelanalysensystemen - Teil1: Ammonium, Nitrat, Nitrit, Chlorid, Orthophosphat, Sulfat
und Silikat durch photometrische Detektion (ISO 15923-1:2013)
Qualité de l'eau - Détermination de paramètres sélectionnés par des systèmes d'analyse
discrète - Partie 1: Ammonium, nitrate, nitrite, chlorure, orthophosphate, sulfate et
silicate par détection photométrique (ISO 15923-1:2013)
Ta slovenski standard je istoveten z: prEN ISO 15923-1
ICS:
13.060.50 Preiskava vode na kemične Examination of water for
snovi chemical substances
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 15923-1
First edition
2013-12-15
Water quality — Determination of
selected parameters by discrete
analysis systems —
Part 1:
Ammonium, nitrate, nitrite, chloride,
orthophosphate, sulfate and silicate
with photometric detection
Qualité de l’eau — Détermination de paramètres sélectionnés par des
systèmes d’analyse discrète —
Partie 1: Ammonium, nitrate, nitrite, chlorure, orthophosphate,
sulfate et silicate par détection photométrique
Reference number
ISO 15923-1:2013(E)
©
ISO 2013
ISO 15923-1:2013(E)
© ISO 2013
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Published in Switzerland
ii © ISO 2013 – All rights reserved

ISO 15923-1:2013(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Interferences . 2
5 Reagents . 2
6 Apparatus . 2
7 Sampling and sample preparation . 2
8 Calibration . 3
8.1 Calibration function . 3
8.2 Calibration validity check . 3
9 Procedure. 3
10 Calculation . 4
11 Expression of results . 4
12 Test report . 4
Annex A (normative) Correction for inherent colour . 6
Annex B (normative) Determination of ammonium . 7
Annex C (normative) Determination of the sum of nitrate and nitrite by the hydrazine method .9
Annex D (normative) Determination of nitrite .12
Annex E (normative) Determination of chloride by the thiocyanate method .14
Annex F (normative) Determination of orthophosphate .16
Annex G (normative) Determination of sulfate by the turbidimetric method .19
Annex H (normative) Determination of silicate .21
Annex I (informative) Performance data .23
Bibliography .25
ISO 15923-1:2013(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.
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. 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. 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.
The committee responsible for this document is ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
ISO 15923 consists of the following parts, under the general title Water quality — Determination of
selected parameters by discrete analysis systems:
— Part 1: Ammonium, nitrate, nitrite, chloride, orthophosphate, sulfate and silicate with photometric detection
iv © ISO 2013 – All rights reserved

ISO 15923-1:2013(E)
Introduction
Many photometric determinations can be automated with a discrete analysis system. With one single
apparatus, a large number of different parameters can be determined, and the parameters to be determined
can be specified for each sample. Working with small volumes requires less sample material and reagent.
Samples that fall beyond the normal measuring range can either be automatically diluted or measured
again with a different measuring range.
This part of ISO 15923 specifies methods for the automatic determination of ammonium, nitrate, nitrite,
chloride, orthophosphate, and silicate with photometric detection and a turbidimetric determination
of sulfate using a discrete analysis system. The field of application is water (ground, potable, surface,
waste, eluates, and boiler water).
INTERNATIONAL STANDARD ISO 15923-1:2013(E)
Water quality — Determination of selected parameters by
discrete analysis systems —
Part 1:
Ammonium, nitrate, nitrite, chloride, orthophosphate,
sulfate and silicate with photometric detection
WARNING — Persons using this part of ISO 15923 should be familiar with normal laboratory
practice. This part of ISO 15923 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 in accordance with this part of
ISO 15923 be carried out by suitably qualified staff.
1 Scope
This part of ISO 15923 specifies methods for the automatic performance of spectrophotometric and
turbidimetric analyses with a discrete analysis system for determining ammonium, nitrate, nitrite,
chloride, orthophosphate, sulfate, and silicate. The field of application is ground, potable, surface, waste,
eluates, and boiler water.
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
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
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 Principle
A discrete analysis system is an automated system for spectrophotometric and turbidimetric
determinations.
The colour reactions take place in reaction cells, which may be cuvettes, in an incubator. For each
determination, a separate reaction cell is used. Preset volumes of the sample and the reagents are
pipetted into the cells and mixed.
After expiry of the incubation period, the absorbance of the solution is measured at the wavelength
applicable to the determination. This is done by passing the cuvettes through the photometer or by
transferring the measuring solution from the reaction cells to a photometer with a flow-through cell.
ISO 15923-1:2013(E)
4 Interferences
Particles present in the sample can lead to blockages and will interfere with the photometric
measurement. Filtration of all samples through a 0,45 μm membrane filter is recommended, except for
the determination of total phosphate and Kjeldahl nitrogen digests (see Annexes B and F). Particles can
also be removed by settlement, centrifugation, or dialysis.
This method is applicable to samples in a pH range from 5 to 9, which covers most natural waters.
Samples outside this range may require pH correction.
Inherent colour or turbidity of the sample interferes with the analysis. On the prevention of such
interference, see Annex A. Interferences specific to each parameter are discussed in Annexes B to H.
NOTE Interference by inherent colour shall be compensated by measuring the absorbance of the sample
before the addition of the chromogenic reagent (sample blanking) or by making use of a compensating solution
(measuring solution withou
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