SIST EN ISO 15681-2:2005

Water quality - Determination of orthophosphate and total phosphorus contents by flow analysis (FIA and CFA) - Part 2: Method by continuous flow analysis (CFA) (ISO 15681-2:2003)

ISO 15681-2:2003 specifies CFA methods for the determination of orthophosphate in the mass concentration range from 0,01 mg/l to 1,00 mg/l P, and total phosphorus in the mass concentration range from 0,10 mg/l to 10,0 mg/l P. The method includes the digestion of organic phosphorus compounds and the hydrolysis of inorganic polyphosphate compounds, performed either manually as described in ISO 6878 or with an integrated UV digestion and hydrolysis unit.
ISO 15681-2:2003 is applicable to various types of water (such as ground, drinking, surface, leachate and waste water). The range of application may be changed by varying the operating conditions.
This method is also applicable to the analysis of seawater, but with changes in sensitivity, by adaptation of the carrier and calibration solutions to the salinity of the samples.

Wasserbeschaffenheit - Bestimmung von Othophosphat und Gesamtphosphor mittels Fließanalytik (FIA und CFA) - Teil 2: Verfahren mittels kontinuierlicher Durchflussanalyse (CFA) (ISO 15681-2:2003)

Dieser Teil von ISO 15681 legt ein CFA-Verfahren für die Bestimmung von Orthophosphat in Massenkonzentrationen von 0,01 mg/l bis 1,00 mg/l P und Gesamtphosphor für Massenkonzentrationen von 0,1 mg/l bis 10 mg/l P fest. Das Verfahren schließt den Aufschluss organischer Phosphorverbindungen und die Hydrolyse anorganischer Polyphosphat-Verbindungen, durchgeführt entweder nach ISO 6878, [5], [6] oder mit einem integrierten UV-Aufschluss und Hydrolyse ein.
Dieser Teil von ISO 15681 ist auf unterschiedliche Wässer anwendbar (wie Grund-, Trink-, Oberflächen-wasser, Eluate und Abwasser). Der Anwendungsbereich kann durch Veränderung der Betriebsbedingungen variiert werden.
Das Verfahren kann auch auf Meerwasser angewandt werden, jedoch unter Änderung der Empfindlichkeit; die Träger- und Bezugslösungen müssen an die Salinität der Probe angepasst werden.

Qualité de l'eau - Dosage des orthophosphates et du phosphore total par analyse en flux (FIA et CFA) - Partie 2: Méthode par analyse en flux continu (CFA) (ISO 15681-2:2003)

L'ISO 15681-2:2003 spécifie des méthodes par analyse en flux continu (CFA) pour le dosage des orthophosphates dans le domaine de concentrations en masse allant de 0,01 mg/l à 1,00 mg/l (P), et pour le dosage du phosphore total dans le domaine de concentrations en masse allant de 0,10 mg/l à 10,0 mg/l (P). La méthode comprend la digestion des composés organiques du phosphore et l'hydrolyse des composés de polyphosphate inorganique, elle est réalisée soit manuellement comme décrit dans l'ISO 6878, soit avec un dispositif de digestion UV intégrée et une unité d'hydrolyse.
L'ISO 15681-2:2003 est applicable à différents types d'eau (tels que eau souterraine, eau potable, eau de surface, lixiviats et eaux usées). Il est possible de modifier le domaine d'application en faisant varier les conditions opératoires.
Cette méthode est également applicable à l'analyse de l'eau de mer moyennant une modification de la sensibilité et une adaptation des solutions vecteurs et des solutions d'étalonnage à la salinité des échantillons.

Kakovost vode - Določanje ortofosfata in celotnega fosforja s pretočno analizo (FIA in CFA) - 2. del: Metoda s kontinuirno pretočno analizo (CFA) (ISO 15681-2:2003)

General Information

• Status: Withdrawn
• Publication Date: 31-Jan-2005
• Withdrawal Date: 03-Feb-2019
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: KAV - Water quality
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 01-Feb-2019
• Due Date: 24-Feb-2019
• Completion Date: 04-Feb-2019
• 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: EN ISO 15681-2:2004 - Water quality - Determination of orthophosphate and total phosphorus contents by flow analysis (FIA and CFA) - Part 2: Method by continuous flow analysis (CFA) (ISO 15681-2:2003)

Relations

• Replaced By: SIST EN ISO 15681-2:2019 - Water quality - Determination of orthophosphate and total phosphorus contents by flow analysis (FIA and CFA) - Part 2: Method by continuous flow analysis (CFA) (ISO 15681-2:2018)
• Effective Date: 01-May-2019
• Splited From: OSIST prEN ISO 15681-1:2004 - Water quality - Determination of phosphate and total phosphorus contents by flow analysis (FIA and CFA) - Part 1: Method by FIA
• Effective Date: 08-Mar-2023
• Parent: OSIST prEN ISO 15681-1:2004 - Water quality - Determination of phosphate and total phosphorus contents by flow analysis (FIA and CFA) - Part 1: Method by FIA
• Effective Date: 22-Dec-2008

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 15681-2:2005
01-februar-2005
.DNRYRVWYRGH±'RORþDQMHRUWRIRVIDWDLQFHORWQHJDIRVIRUMDVSUHWRþQRDQDOL]R
),$LQ&)$±GHO0HWRGDVNRQWLQXLUQRSUHWRþQRDQDOL]R&)$,62

Water quality - Determination of orthophosphate and total phosphorus contents by flow
analysis (FIA and CFA) - Part 2: Method by continuous flow analysis (CFA) (ISO 15681-
2:2003)
Wasserbeschaffenheit - Bestimmung von Othophosphat und Gesamtphosphor mittels
Fließanalytik (FIA und CFA) - Teil 2: Verfahren mittels kontinuierlicher Durchflussanalyse
(CFA) (ISO 15681-2:2003)
Qualité de l'eau - Dosage des orthophosphates et du phosphore total par analyse en flux
(FIA et CFA) - Partie 2: Méthode par analyse en flux continu (CFA) (ISO 15681-2:2003)
Ta slovenski standard je istoveten z: EN ISO 15681-2:2004
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
SIST EN ISO 15681-2:2005 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 15681-2:2005

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SIST EN ISO 15681-2:2005
EUROPEAN STANDARD
EN ISO 15681-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2004
ICS 13.060.50
English version
Water quality - Determination of orthophosphate and total
phosphorus contents by flow analysis (FIA and CFA) - Part 2:
Method by continuous flow analysis (CFA) (ISO 15681-2:2003)
Qualité de l'eau - Dosage des orthophosphates et du Wasserbeschaffenheit - Bestimmung von Othophosphat
phosphore total par analyse en flux (FIA et CFA) - Partie 2: und Gesamtphosphor mittels Fließanalytik (FIA und CFA) -
Méthode par analyse en flux continu (CFA) (ISO 15681- Teil 2: Verfahren mittels kontinuierlicher Durchflussanalyse
2:2003) (CFA) (ISO 15681-2:2003)
This European Standard was approved by CEN on 21 December 2004.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, 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
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15681-2:2004: E
worldwide for CEN national Members.

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SIST EN ISO 15681-2:2005
EN ISO 15681-2:2004 (E)






Foreword



The text of ISO 15681-2:2003 has been prepared by Technical Committee ISO/TC 147 "Water
quality” of the International Organization for Standardization (ISO) and has been taken over as
EN ISO 15681-2:2004 by 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 June 2005, and conflicting national
standards shall be withdrawn at the latest by June 2005.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.


Endorsement notice

The text of ISO 15681-2:2003 has been approved by CEN as EN ISO 15681-2:2004 without any
modifications.

2

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SIST EN ISO 15681-2:2005


INTERNATIONAL ISO
STANDARD 15681-2
First edition
2003-12-15


Water quality — Determination of
orthophosphate and total phosphorus
contents by flow analysis (FIA and
CFA) —
Part 2:
Method by continuous flow analysis
(CFA)
Qualité de l'eau — Dosage des orthophosphates et du phosphore total
par analyse en flux (FIA et CFA) —
Partie 2: Méthode par analyse en flux continu (CFA)





Reference number
ISO 15681-2:2003(E)
©
ISO 2003

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SIST EN ISO 15681-2:2005
ISO 15681-2:2003(E)
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ii © ISO 2003 – All rights reserved

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SIST EN ISO 15681-2:2005
ISO 15681-2:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Interferences. 2
3.1 General interferences. 2
3.2 Interferences in the determination of total-P . 2
4 Principle. 2
4.1 Determination of orthophosphate . 2
4.2 Total phosphorus with manual digestion. 3
4.3 Total phosphorus with integral UV digestion and hydrolysis. 3
5 Reagents. 3
6 Apparatus. 7
6.1 Continuous-flow analysis (CFA). 7
6.2 Additional apparatus. 7
6.3 Additional apparatus for the determination of total phosphorus after integral digestion . 8
7 Sampling and sample preparation . 8
8 Procedure. 8
8.1 Preparation for analysis . 8
8.2 Instrument performance check. 8
8.3 Reagent blank check . 9
8.4 Calibration. 9
8.5 Check of UV digestion and hydrolysis for total P determination (see Figure A.2). 9
8.6 Measurement. 10
8.7 Closing down the system. 10
9 Calculation of results. 10
10 Expression of results. 10
11 Test report. 10
Annex A (informative) Examples of a CFA system . 12
Annex B (informative) Precision and accuracy . 14
Annex C (informative) Determination of orthophosphate-P and total-P by CFA and tin(II) chloride
reduction. 15
Bibliography . 16

© ISO 2003 – All rights reserved iii

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SIST EN ISO 15681-2:2005
ISO 15681-2:2003(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 15681-2 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
ISO 15681 consists of the following parts, under the general title Water quality — Determination of
orthophosphate and total phosphorus contents by flow analysis (FIA and CFA):
— Part 1: Method by flow injection analysis (FIA)
— Part 2: Method by continuous flow analysis (CFA)
iv © ISO 2003 – All rights reserved

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SIST EN ISO 15681-2:2005
ISO 15681-2:2003(E)
Introduction
Methods of determining water quality using flow analysis automated wet chemical procedures and are
particularly suitable for the processing of many analytes in water in large sample series at a high analysis
frequency.
[1], [2] [3]
Analysis can be performed by flow injection analysis (FIA) or continuous flow analysis (CFA) . Both
methods share the feature of an automatic dosage of the sample into a flow system (manifold) where the
analyte in the sample reacts with the reagent solutions on its way through the manifold. The sample
preparation may be integrated in the manifold. The amount of reaction product is measured in a flow detector
(e.g. flow photometer). This part of ISO 15681 describes the CFA method.
The user should be aware that particular problems could require the specification of additional marginal
conditions.

© ISO 2003 – All rights reserved v

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SIST EN ISO 15681-2:2005

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SIST EN ISO 15681-2:2005
INTERNATIONAL STANDARD ISO 15681-2:2003(E)

Water quality — Determination of orthophosphate and total
phosphorus contents by flow analysis (FIA and CFA) —
Part 2:
Method by continuous flow analysis (CFA)
WARNING — Persons using this part of ISO 15681 should be familiar with normal laboratory practice.
This part of ISO 15681 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. Molybdate and antimony waste solutions
should be disposed of properly. It is absolutely essential that tests conducted according to this part of
ISO 15681 be carried out by suitably qualified staff.
1 Scope
This part of ISO 15681 specifies CFA methods for the determination of orthophosphate in the mass
concentration range from 0,01 mg/l to 1,00 mg/l P, and total phosphorus in the mass concentration range from
0,10 mg/l to 10,0 mg/l P. The method includes the digestion of organic phosphorus compounds and the
[5], [6]
hydrolysis of inorganic polyphosphate compounds, performed either manually as described in ISO 6878
or with an integrated UV digestion and hydrolysis unit.
This part of ISO 15681 is applicable to various types of water (such as ground, drinking, surface, leachate and
waste water). The range of application may be changed by varying the operating conditions.
This method is also applicable to the analysis of seawater, but with changes in sensitivity, by adaptation of the
carrier and calibration solutions to the salinity of the samples.
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 — Specifications and test methods
ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design on sampling programmes
ISO 5667-2, Water quality — Sampling — Part 2: Guidance on sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Guidance on the preservation and handling of water
samples
1)
ISO 6878:— , Water quality — Determination of phosphorus — Ammonium molybdate spectrometric method

1) To be published.
© ISO 2003 – All rights reserved 1

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SIST EN ISO 15681-2:2005
ISO 15681-2:2003(E)
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
3 Interferences
3.1 General interferences
ISO 6878:—, Annex B gives a list of general interferences. In addition, or contrary to the cited standard, the
following guidelines apply.
a) Arsenate causes serious interference. 100 µg/l As, present as arsenate, results in a response
comparable to approximately 30 µg/l P.
b) If the silicate concentration in samples is not greater than 60 times the phosphorus concentration,
interferences by silicate can be neglected.
c) Fluoride interference is significant above 50 mg/l.
d) Nitrite interference is significant above 5 mg/l. The interference can be eliminated by acidifying samples
after collection.
e) For samples containing high concentrations of oxidizing agents, the amount of added reduction reagent
can be insufficient. In this case, remove the oxidizing material prior to digestion.
f) The self-absorption of the sample can be compensated by measuring, in addition to the sample signal
(8.6), the signal of the sample without the admixture of the reagents. In this case, the difference of the two
responses is used for the evaluation (Clause 9).
3.2 Interferences in the determination of total-P
Samples containing solids or suspended particles can show low values when analysed by the UV method, if
the particles are not completely transported into the UV unit. The error can be minimized by stirring the
sample immediately before sampling, in order to ensure that a representative sample is delivered into the
analyser, and by reducing the particle size.
The interferences from silicate, nitrite, fluoride and iron described for the orthophosphate determination are
generally not observed in the UV method, due to the pre-digestion and the higher analytical range.
The efficiency of the UV digestion can be affected for water samples with chemical oxygen demand (COD)
values of more than 10 times the highest concentrations of the calibration solutions (5.21). In this case, the
sample should be diluted.
4 Principle
4.1 Determination of orthophosphate
The sample is mixed with a surfactant solution, followed by an acidic solution containing molybdate and
antimony ions. The resulting phospho-antimony-molybdate complex is reduced by ascorbic acid to
[4], [5]
molybdenum blue .
2 © ISO 2003 – All rights reserved

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SIST EN ISO 15681-2:2005
ISO 15681-2:2003(E)
4.2 Total phosphorus with manual digestion
Phosphorus compounds in the sample are oxidized manually with a potassium peroxodisulfate solution, in
accordance with ISO 6878, or with an equivalent procedure. The resulting orthophosphate is determined by
the molybdenum blue reaction using the colour reaction described in 4.1. The samples can be neutralized
manually according to ISO 6878 or by taking into account the amount of acid used in this procedure when
calculating the acid to be used in the molybdenum reagent.
4.3 Total phosphorus with integral UV digestion and hydrolysis
The sample is mixed with potassium peroxodisulfate and passed through a UV digestor, followed by acid
digestion to hydrolyse polyphosphates. The resulting orthophosphate is measured using the colour reaction
described in 4.1.
5 Reagents
Use analytical grade chemicals unless otherwise specified.
5.1 Water complying to grade 1 of ISO 3696.
The phosphate blank value shall be checked (8.3).
5.2 Sulfuric acid, H SO .
2 4
5.2.1 Sulfuric acid (I), ρ = 1,84 g/ml; 98 % (mass fraction).
5.2.2 Sulfuric acid (II), c(H SO ) = 2,45 mol/l.
2 4
To approximately 800 ml of water (5.1), carefully add 136 ml of sulfuric acid (I) (5.2.1) while stirring. Cool and
dilute to 1 000 ml with water (5.1).
5.3 Ammonium heptamolybdate tetrahydrate, (NH ) Mo O ⋅ 4 H O.
4 6 7 24 2
5.4 Antimony potassium tartrate hemihydrate, K(SbO)C H O ⋅ 0,5 H O.
4 4 6 2
5.5 Ascorbic acid, C H O .
6 8 6
5.6 Sodium dodecyl sulfate, NaC H SO .
12 25 4
5.7 Potassium peroxodisulfate, K S O .
2 2 8
5.8 Potassium dihydrogen phosphate, KH PO , dried at 105 °C ± 5 °C to constant mass.
2 4
5.9 Potassium pyrophosphate, K P O .
4 2 7
5.10 Organophosphorus compounds to check the UV digestion.
5.10.1 Pyridoxal-5-phosphate monohydrate, C H NO P ⋅ H O or alternatively:
8 10 6 2
5.10.2 Disodium phenylphosphate, C H Na PO .
6 5 2 4
5.11 Surfactant solutions
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SIST EN ISO 15681-2:2005
ISO 15681-2:2003(E)
5.11.1 Surfactant solution I, [see (A) in Figure A.1].
Dissolve 1 g of sodium dodecyl sulfate (5.6) in about 800 ml of water (5.1) and dilute to 1 000 ml.
The solution is stable for 6 months if stored at room temperature.
5.11.2 Surfactant solution II, [see (B) in Figure A.1, and S1 in Figure A.2].
Dissolve 10 g of sodium dodecyl sulfate (5.6) in about 800 ml of water (5.1) and dilute to 1 000 ml.
The solution is stable for 6 months if stored at room temperature.
5.12 Moly
...