SIST EN ISO 15682:2001
(Main)Water quality - Determination of chloride by flow analysis (CFA and FIA) and photometric or potentiometric detection (ISO 15682:2000)
Water quality - Determination of chloride by flow analysis (CFA and FIA) and photometric or potentiometric detection (ISO 15682:2000)
The procedure is outlined for the analysis of chloride, in the range of 1 to 1000 mg/l, in various water samples (e.g. ground-, drinking-, surface- and waste water, and leachates). On an individual basis the range of the analysis can be changed.
Wasserbeschaffenheit - Bestimmung von Chlorid mittels Fließanalyse (CFA und FIA) und photometrischer oder potentiometrischer Detektion (ISO 15682:2000)
Diese Internationale Norm legt zwei Verfahren zur Bestimmung von Chlorid mittels Fließanalyse fest. Die beiden Verfahren werden in getrennten Abschnitten wie folgt beschrieben:
a) Abschnitt 3: Bestimmung von Chlorid mittels Fließanalyse und photometrischer Detektion.
b) Abschnitt 4: Bestimmung von Chlorid mittels Fließanalyse und potentiometrischer Detektion.
Beide Verfahren sind geeignet zur Analyse von Wasser und Abwasser (einschließlich Eluaten) im Konzentrationsbereich von 1 mg/l bis 1000 mg/l . Der Arbeitsbereich kann individuell angepasst werden.
Nach Verdünnung können auch Proben mit einer Chlorid-Massenkonzentration > 1000 mg/l analysiert werden.
Das Verfahren nach Abschnitt 4 ist auch auf trübe und/oder gefärbte Wasserproben anwendbar.
ANMERKUNG Aus Gründen des Umweltschutzes ist dem potentiometrischen Verfahren der Vorzug zu geben, da hierbei keine toxischen Reagenzien eingesetzt werden. Bei Anwendung des photometrischen Verfahrens sollten flüchtige und feste Abfallstoffe, die Quecksilber enthalten, entsprechend den Umweltschutzrichtlinien entsorgt werden.
Qualité de l'eau - Dosage du chlorure par analyse en flux (CFA et FIA) et par détection photométrique ou potentiométrique (ISO 15682:2000)
La présente Norme internationale spécifie deux méthodes pour le dosage des chlorures par analyse en flux. Ces deux méthodes de base sont exposées dans des articles différents : a) Article 3 : Dosage des chlorures par analyse en flux et détection photométrique ; b) Article 4 : Dosage des chlorures par analyse en flux et détection potentiométrique. Les deux méthodes sont applicables à l'analyse des eaux et des eaux résiduaires (y compris les eaux de lessivage), dans le domaine de concentration de 1 mg/l à 1000 mg/l. Le domaine d'analyse peut être modifié au cas par cas. Les échantillons ayant une concentration en chlorures supérieure à 1000 mg/l peuvent également être analysés, à condition d'avoir subi au préalable une dilution. La méthode décrite dans l'article 4 est également applicable aux échantillons turbides et/ou colorés.
NOTE Du point de vue écologique, il est préférable d'utiliser la méthode potentiométrique, car elle évite l'emploi de réactifs toxiques. Lorsque la méthode photométrique est employée, il convient que les déchets volatils et solides contenant du mercure soient éliminés conformément aux réglementations environnementales.
Kakovost vode - Določevanje klorida s pretočnima analizama (CFA in FIA) in fotometrično ali potenciometrično detekcijo (ISO 15682:2000)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 15682:2001
01-december-2001
.DNRYRVWYRGH'RORþHYDQMHNORULGDVSUHWRþQLPDDQDOL]DPD &)$LQ),$ LQ
IRWRPHWULþQRDOLSRWHQFLRPHWULþQRGHWHNFLMR ,62
Water quality - Determination of chloride by flow analysis (CFA and FIA) and photometric
or potentiometric detection (ISO 15682:2000)
Wasserbeschaffenheit - Bestimmung von Chlorid mittels Fließanalyse (CFA und FIA)
und photometrischer oder potentiometrischer Detektion (ISO 15682:2000)
Qualité de l'eau - Dosage du chlorure par analyse en flux (CFA et FIA) et par détection
photométrique ou potentiométrique (ISO 15682:2000)
Ta slovenski standard je istoveten z: EN ISO 15682:2001
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
SIST EN ISO 15682:2001 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 15682:2001
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SIST EN ISO 15682:2001
EUROPEAN STANDARD
EN ISO 15682
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2001
ICS 13.060.50
English version
Water quality - Determination of chloride by flow analysis (CFA
and FIA) and photometric or potentiometric detection (ISO
15682:2000)
Qualité de l'eau - Dosage du chlorure par analyse en flux Wasserbeschaffenheit - Bestimmung von Chlorid mittels
(CFA et FIA) et par détection photométrique ou Fließanalyse (CFA und FIA) und photometrischer oder
potentiométrique (ISO 15682:2000) potentiometrischer Detektion (ISO 15682:2000)
This European Standard was approved by CEN on 18 June 2001.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, 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
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15682:2001 E
worldwide for CEN national Members.
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SIST EN ISO 15682:2001
EN ISO 15682:2001 (E)
CORRECTED 2001-11-07
Foreword
The text of the International Standard from Technical Committee ISO/TC 147 "Water quality"
of the International Organization for Standardization (ISO) has been taken over as an
European Standard 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 February 2002, and conflicting national
standards shall be withdrawn at the latest by February 2002.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United
Kingdom.
Endorsement notice
The text of the International Standard ISO 15682:2000 has been approved by CEN as a
European Standard without any modifications.
NOTE: Normative references to International Standards are listed in annex ZA (normative).
2
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SIST EN ISO 15682:2001
EN ISO 15682:2001 (E)
Annex ZA (normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions
of any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
NOTE Where an International Publication has been modified by common modifications,
indicated by (mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 3696 1987 Water for analytical laboratory use - EN ISO 3696 1995
Specification and test methods
3
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SIST EN ISO 15682:2001
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SIST EN ISO 15682:2001
INTERNATIONAL ISO
STANDARD 15682
First edition
2000-07-15
Water quality — Determination of chloride
by flow analysis (CFA and FIA) and
photometric or potentiometric detection
Qualité de l'eau — Dosage du chlorure par analyse en flux (CFA et FIA) et
par détection photométrique ou potentiométrique
Reference number
ISO 15682:2000(E)
©
ISO 2000
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SIST EN ISO 15682:2001
ISO 15682:2000(E)
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ii © ISO 2000 – All rights reserved
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SIST EN ISO 15682:2001
ISO 15682:2000(E)
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative reference .1
3 Determination of chloride by flow analysis (FIA and CFA) with photometric detection.1
4 Determination of chloride by flow analysis (FIA and CFA) with potentiometric detection.7
5 Expression of results .10
6 Test report.10
Annex A (informative) Performance characteristics.12
Annex B (informative) Examples of flow diagrams.14
Annex C (informative) Determination of chloride by flow analysis (FIA and CFA) and potentiometric
detection with a single calibration function for the range 10 mg/l to 1 000 mg/l .20
Bibliography.21
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SIST EN ISO 15682:2001
ISO 15682:2000(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.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 15682 was prepared by Technical Committee ISO/TC 147, Water quality,
Subcommittee SC 2, Physical, chemical and biochemical methods.
Annexes A, B and C of this International Standard are for information only.
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SIST EN ISO 15682:2001
ISO 15682:2000(E)
Introduction
Methods using flow analysis automatize wet chemical procedures and are particularly suitable for the processing of
many analytes in water in large sample series at a high analysis frequency (up to 100 samples per hour).
Differentiation is required between flow injection analysis (FIA) [1, 2], and continuous flow analysis (CFA) [3]. Both
methods share the feature of 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 amount of reaction product is measured in a flow detector (e.g. photometer, or ion-
selective electrode). The detector produces a signal from which the concentration of the parameter is calculated.
It should be investigated whether and to what extent particular problems will require the specification of additional
marginal conditions.
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SIST EN ISO 15682:2001
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SIST EN ISO 15682:2001
INTERNATIONAL STANDARD ISO 15682:2000(E)
Water quality — Determination of chloride by flow analysis (CFA
and FIA) and photometric or potentiometric detection
1 Scope
This International Standard specifies two methods for the determination of chloride by flow analysis. The two basic
methods are covered in separate clauses as follows:
a) Clause 3: Determination of chloride by flow analysis and photometric detection.
b) Clause 4: Determination of chloride by flow analysis and potentiometric detection.
Both methods are applicable to the analysis of water and waste water (including leachates) containing chloride in
the concentration range from 1 mg/l to 1 000 mg/l. On a case-by-case basis the range of the analysis can be
changed.
After dilution, samples with a chloride concentration > 1 000 mg/l can also be analysed.
The method with potentiometric detection is also applicable to turbid and/or coloured samples.
NOTE From the ecological point of view, the potentiometric method is preferable because it avoids the use of toxic
reagents. When the photometric method is applied, volatile and solid wastes containing mercury should be discarded in
accordance with environmental regulations.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, this publication do
not apply. However, parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent edition of the normative document 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.
3 Determination of chloride by flow analysis (FIA and CFA) with photometric detection
3.1 Principle
When using FIA, the sample is injected into a continuous flowing carrier stream (water) through an injection valve.
When using CFA, the sample is pumped into the carrier stream via a peristaltic pump. Depending on the
concentration of the sample, the sample is diluted with water. A reagent solution (mercury thiocyanate iron(III)
nitrate solution), also pumped by the peristaltic pump, is then mixed with the sample stream. The thiocyanate,
which is liberated by the chloride, reacts with the iron(III) ions to form a red-coloured iron(III) thiocyanate complex
[4], [5], [6].
It is absolutely essential that the tests described in this International Standard be carried out by suitably qualified
staff.
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ISO 15682:2000(E)
3.2 Interferences
The analysis is subject to interferences as follows:
a) chemicals which liberate thiocyanate (i.e. the mercury thiocyanate), for example bromide and iodide ions;
Bromide causes interference when present in concentrations exceeding 30 mg/l. The mass concentration of
bromide and iodide can be determined in terms of chloride equivalents, and the result can be considered in the
calculation procedure (3.7).
b) chemicals which form a coloured product with the reagent used in the analysis (e.g. thiocyanate and sulfide
ions);
When sulfide ions are expected (in surface, waste and drain waters), the sample should be treated with 0,5 ml
of hydrogen peroxide (3.3.7) per 100 ml of sample and analysed after at least 5 min.
c) the natural colour of the sample.
In this case dilution of the sample or in-line dialysis is recommended.
Filtration of the sample before analysis is advisable for samples with particle sizes larger than 100 �m(for example
surface and waste waters), otherwise the particles in the sample may clog the transport tubes.
The pH of the sample shall be adjusted to a value between pH 3 and pH 10.
The self-absorbance of the sample matrix can be compensated for by measuring, in addition to the sample signal
(3.6.5), the signal of the sample in a parallel channel without the admixture of the reagents. The parallel channel
can be integrated into the flow system (3.4.1 or 3.4.2). In this case the difference between the two responses (with
and without addition of reagents) is used for the calculation of results (in accordance with 3.7). The difference
between the two measured signals is used in equation (2) (3.7).
3.3 Reagents
All chemicals required shall be of recognized analytical grade.
3.3.1 Water, of grade 1, in accordance with ISO 3696.
3.3.2 Mercury(II) thiocyanate, Hg(SCN) .
2
WARNING — Volatile and solid wastes containing mercury should be discarded in accordance with
environmental regulations.
3.3.3 Methanol,CH OH.
3
WARNING — Methanol is toxic and should be handled with care.
3.3.4 Nitric acid I, HNO ,� = 1,4 g/ml, mass fraction = 65 %.
3
3.3.5 Iron(III) nitrate nonahydrate, Fe(NO ) � 9H O.
3 3 2
3.3.6 Sodium chloride, NaCl, dried at 105�C� 5�C.
3.3.7 Hydrogen peroxide,H O , � = 1,11 g/ml, mass fraction = 30 %.
2 2
3.3.8 Detergent solution, polyethyleneglycol dodecyl ether, HO-CH CH -O-C H .
2 2 12 25
Freezing range 33�Cto41�C, solution, mass fraction = 30 %.
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SIST EN ISO 15682:2001
ISO 15682:2000(E)
The solution is stable for one month.
3.3.9 Reagent solution (R in Figures B.1 to B.4).
a) Dissolve 31 g of iron(III) nitrate nonahydrate (3.3.5) in approximately 500 ml of water.
b) In a 1 000 ml volumetric flask dissolve 0,62 g of mercury thiocyanate (3.3.2) in 150 ml of methanol (3.3.3) while
constantly stirring. Add 100 ml of water (3.3.1), 3,4 ml of nitric acid I (3.3.4), and the above-mentioned aqueous
solution of iron nitrate. Make up to volume with water (3.3.1). Stir the solution for 2 h and filter.
The solution is stable for three months in a dark place.
c) Before analysis, degas the reagents for 10 min, e.g. by membrane filtration (under pressure).
3.3.10 Chloride stock solution I,� = 10 000 mg/l.
Dissolve 16,50 g � 0,05 g of sodium chloride (3.3.6) in water (3.3.1) and make up to a volume of 1 000 ml with
water.
The solution is stable for one year.
3.3.11 Chloride stock solution II,� =100mg/l.
Add 5 ml of stock solution I (3.3.10) in a 500 ml volumetric flask and make up to volume with water.
The solution is stable for three months.
3.3.12 Carrier solution for FIA (C1 in Figures B.1 and B.2).
Water (3.3.1) shall be used.
3.3.13 Carrier solutions for CFA (C2 and C3 in Figure B.4).
� C2: Dilute 8 ml of nitric acid I (3.3.4) in approximately 900 ml of water in a 1000 ml volumetric flask. Add 1 ml
of detergent solution (3.3.8) and make up to volume with water.
� C3: Dilute 4 ml of nitric acid I (3.3.4) in approximately 900 ml of water in a 1000 ml volumetric flask. Add 1 ml
of detergent solution (3.3.8) and make up to volume with water.
3.3.14 Calibration solutions.
Prepare the calibration solutions by diluting stock solution I or II (3.3.10 or 3.3.11).
Use a minimum of at least five calibration standards per working range. For example, if six standards are used,
proceed for the working ranges I to III as follows:
a) Range III (1 mg/l to 10 mg/l):
Pipette 1 ml, 3 ml, 5 ml, 6 ml, 8 ml, and 10 ml respectively of stock solution II (3.3.11) into a series of 100 ml
volumetric flasks. Make up to volume with water.
The mass concentrations of chloride in the resulting calibration solution are 1 mg/l, 3 mg/l, 5 mg/l, 6 mg/l,
8 mg/l, and 10 mg/l respectively. These calibration solutions are stable for one week.
b) Range II (10 mg/l to 100 mg/l):
Pipette 10 ml, 30 ml, 50 ml, 60 ml, 80 ml, and 100 ml respectively of stock solution II (3.3.11) into a series of
100 ml volumetric flasks. Make up to volume with water.
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SIST EN ISO 15682:2001
ISO 15682:2000(E)
The mass concentrations of chloride in these calibration solutions are 10 mg/l, 30 mg/l, 50 mg/l, 60 mg/l,
80 mg/l and 100 mg/l respectively. These calibration solutions are stable for one month.
c) Range I (100 mg/l to 1 000 mg/l):
Pipette 1 ml, 3 ml, 5 ml, 6 ml, 8 ml, and 10 ml respectively of stock solution I (3.3.10) into a series of 100 ml
volumetric flasks. Make up to volume with water.
The mass concentrations of chloride in the resulting calibration solution are 100 mg/l, 300 mg/l, 500 mg/l,
600 mg/l, 800 mg/l and 1000 mg/l respectively. These calibration solutions are stable for three months.
NOTE Other concentration ranges are applicable, provided they cover exactly one decade of concentration units.
3.4 Apparatus
3.4.1 Flow injection analysis system (FIA)
The flow injection system shall consist of the following basic components (see Figures B.1 and B.2).
3.4.1.1 Reagent containers.
3.4.1.2 Low-pulse pump.
3.4.1.3 Calibrated chemically resistant pump tubes, if required.
3.4.1.4 Sample injection system with an injection volume of 20�lto100�l.
3.4.1.5 Transport tubes (internal diameter 0,5 mm to 0,8 mm), tube connections and T-connections of
inert material and with minimum dead volumes.
3.4.1.6 Photometer with flow cell, wavelength range 450 nm to 480 nm.
3.4.1.7 Registration unit (e.g. strip chart recorder, integrator or printer/plotter).
In general, peak height signals are evaluated.
3.4.1.8 Autosampler, if required.
3.4.2 Continuous flow analysis system (CFA)
The continuous flow system shall consist of the following basic components (see Figures B.3 and B.4).
3.4.2.1 Sampler or other equipment which provides a reproducible sample and liquid transport.
3.4.2.2 Reagent containers.
3.4.2.3 Low-pulse pump with calibrated chemical resistant pump tubes.
3.4.2.4 Inlet connector made of glass or chemically resistant material, with reproducible air-, sample- and
reagent segmentation, with calibrated transport tubes.
3.4.2.5 Dialysis cell (with a cellulose membrane, e.g. length 150 mm), if dilution or clean-up of samples is
necessary.
3.4.2.6 Photometer with flow cell, wavelength range 450 nm to 480 nm.
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SIST EN ISO 15682:2001
ISO 15682:2000(E)
3.4.2.7 Registration unit (e. g. strip chart recorder, integrator or printer/plotter).
In general peak height signals are evaluated.
3.4.2.8 Autosampler, if required.
NOTE In Figures B.3 and B.4, continuous flow systems with internal diameters of 2 mm (“macroflow”) are described. Similar
systems with an internal diameter of 1 mm (”microflow”) are also allowable.
3.4.3 Additional apparatus
3.4.3.1 Graduated flasks, nominal capacity 100 ml, 200 ml and 1 000 ml.
3.4.3.2 Graduated pipettes, nominal capacity 1 ml to 100 ml.
3.5 Sampling and sample pretreatment
Store the samples in either glass or plastic containers for up to one month. Sample preservation is not required
(see ISO 5667-3).
3.6 Procedure
3.6.1 Preparation of the measurement
a) Assemble the flow analysis system (FIA or CFA) in accordance with the flow diagrams (3.4.1, 3.4.2; Figures
B.1toB.4).
b) Before analysis, insert the tubes of the carrier solutions C1 to C3 (3.3.12, 3.3.13) and the reagent solution
(3.3.9) into the appropriate canisters. Run the system for 10 min. Wait for a stable baseline and adjust the
baseline to zero.
c) When the baseline shows no more drift, the system is ready for analysis. Check the reagent blank in
accordance with 3.6.3 and calibrate in accordance with 3.6.4.
3.6.2 Quality requirements for the measuring system
3.6.2.1 Instrument performance check
The absorbance per centimetre of optical pathlength measured for the calibration solutions (3.3.14) shall be in the
range from 0,03 to 2,0.
NOTE If the photometric detector does not give any absorbance readings, the absorbance may then be determined by
comparison with an external absorbance-measuring spectrometer.
3.6.2.2 Daily sensitivity adjustment
If a recorder for the calculation of results is used, transfer the sample probe into a chloride calibration solution
(3.3.14) with the highest concentration of the selected working range (10 mg/l, 100 mg/l or 1000 mg/l, respectively).
When there is a positive response at the registration unit due to the colour produced from the calibration solution,
adjust the response to read about 95 % of full-scale deflection.
3.6.3 Checking the reagent blank
The reagent solution (3.3.9) shall not exceed an absorbance per centimetre of optical path length of 0,3. Otherwise
consider the water as contaminated with chloride and take alternative steps. The absorbance can be measured by
an external spectrometer.
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ISO 15682:2000(E)
3.6.4 Calibration
Prepare the required calibration solutions for each range according to 3.3.14.
Calibrate each range separately.
To start the calibration, position the output signal to zero.
Calibrate by sequentially applying the calibration solutions and reagent blanks.
Obtain the measured values corresponding to the calibration solutions applied.
The procedure for the calibration and the analysis of samples (3.6.5) shall be the same.
The following general equation (1) for the quadratic equation (see ISO 8466-2) shall apply.
2
y = c� + b� + a (1)
where
y is the measured value, in terms of instrument-related units (absorbance or a unit proportional to the
absorbance);
� is the mass concentration, in milligrams per litre, of chloride in the calibration solutions;
a is the ordinate intercept of the calibration function, in terms of instrument-related units;
b is the parameter of the calibration function in terms of instrument-related units (l/mg);
2 2
c second-order parameter of the calibration function in terms of instrument-related units (l /mg ).
3.6.5 Measurement
Analyse the samples in the same way as the calibration solutions with the flow analysis system FIA or CFA (3.4.1
or 3.4.2) respectively.
Dilute the sample, or use another working range, if the mass concentrations exceed the validity range of the
selected working range.
Verify the validity of the calibration function of the selected working range after each sample series, at the most
after 20 samples, using one calibration solution each for the lower and upper parts of the respective working range.
If necessary recalibrate the system.
3.7 Calculation of results
Determine the mass concentration of chloride in the measuring solution using the measured value obtained as
described in 3.6.5 from the calibration function (1) (3.6.4).
For the calculation use the appropriate calibration function. Do not extrapolate beyond the working range selected.
Calculate � from equation (2):
1
2
�� 2
� � –bc2 – b 2c ––a y c (2)
� � � � � �
��
��
For the explanation of the symbols in this equation, see 3.6.4, equation (1). All dilution steps shall be taken into
account in the calculation.
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4 Determination of chloride by flow analysis (FIA and CFA) with potentiometric
detection
4.1 Principle
For FIA the sample is injected, via an injection valve, into a carrier stream. For CFA the sample is mixed with a
carrier stream. The carrier stream containing the sample is mixed with a buffer solution. The chloride ions are
determined by a specific chloride-ion-selective electrode (with a reference electrode) in a flowcell [7], [8], [9], [10].
4.2 Interferences
– – 2–
Ions that form insoluble substances with silver (Br ,I ,S ) or ions that form complexes with silver ions
– 2–
(CN ,S O ) interfere with this method.
2 3
If sulfides are expected, 0,5 ml of hydrogen peroxide (3.3.7) per 100 ml of the water sample should be added. The
mixture can be analysed after 5 min.
– – –
If Br ,I ,CN ions are expected up to a concentration of 0,1 g/l, mix the sample (1:2) with a solution containing
14,4 g of potassium bromate (4.3.3) and 76 ml of nitric acid II (4.3.4) in 1000 ml of water. After 10 min the sample
can be analysed.
4.3 Reagents
4.3.1 General
See 3.3.1. In addition to the reagents listed in 3.3 the following reagents of ”analytical grade quality” are required.
4.3.2 Potassium nitrate,KNO
.
3
4.3.3 Potassium bromate, KBrO
.
3
4.3.4 Nitric acid II, c(HNO )=1mol/l.
3
4.3.5 Carrier solution for the FIA method for ranges I to III(C4inFigureB.5).
If there are no interfering ions (see 4.2) present in the sample, use water as carrier solution C4. If there are
interfering ions (see 4.2) present in the sample, make up the carrier solution C4 as follows:
In a 1 000 ml volumetric flask dissolve 7,2 g of potassium bromate (4.3.3) and 38 ml of nitric acid II (4.3.4) in
approximately 800 ml of water. Make up to volume with water.
This solution shall be prepared fresh daily.
4.3.6 Ionic strength adjustment buffer (ISA) solution for FIA (P1 in Figure B.5)
4.3.6.1 FIA ISA solution for samples without interfering ions (see 4.2)
a) For ranges III and II (1 mg/l to 10 and 10 mg/l to 100 mg/l chloride):
In a 1 000 ml volumetric flask dissolve 3 ml of nitric acid II (4.3.4) and 10,1 g of potassium nitrate (4.3.2) in
approximately 800 ml of water. Make up to volume with water.
This solution may be stored for one month.
b) For range I (100 mg/l to 1 000 mg/l):
© ISO 2000 – All rights reserved 7
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SIST EN ISO 15682:2001
ISO 15682:2000(E)
In a 1 000 ml volumetric flask dissolve 50,5 g of potassium nitrate (4.3.2) and 3 ml of nitric acid II (4.3.4) in
approximately 800 ml of water. Make up to volume with water.
This solution may be stored for one month.
–
4.3.6.2 FIA ISA solution for samples with interfering ions (4.2) in the range (1 mg/l to 1000 mg/l Cl )
In a 1 000 ml volumetric flask dissolve 7,2 g of potassium bromate (4.3.3) and 38 ml of nitric acid II (4.3.4) in
app
...
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