SIST EN ISO 13395:1999
(Main)Water quality - Determination of nitrite nitrogen and nitrate nitrogen and the sum of both by flow analysis (CFA and FIA) and spectrometric detection (ISO 13395:1996)
Water quality - Determination of nitrite nitrogen and nitrate nitrogen and the sum of both by flow analysis (CFA and FIA) and spectrometric detection (ISO 13395:1996)
According to the methods specified in this document nitrite and nitrate by be determined in large sample series and a high analysis frequency. The method includes an automatic dosage.
Wasserbeschaffenheit - Bestimmung von Nitritstickstoff, Nitratstickstoff und der Summe von beiden mit der Fließanalytik (CFA und FIA) und spektrometrischer Detektion (ISO 13395:1996)
Qualité de l'eau - Détermination de l'azote nitreux et de l'azote nitrique et de la somme des deux par analyse en flux (CFA et FIA) et détection spectrométrique (ISO 13395:1996)
La présente Norme internationale prescrit une méthode pour la détermination de l'azote nitreux, de l'azote nitrique ou de la somme des deux dans différentes eaux (par exemple eau souterraine, eau potable, eau de surface et eaux usées), en concentrations en masse dans les gammes allant de 0,01 mg/l à 1 mg/l pour l'azote nitreux et de 0,2 mg/l à 20 mg/l pour la somme des azotes nitreux et nitrique, dans les deux cas pour des échantillons non dilués. Le domaine d'application peut être modifié en faisant varier les conditions de travail.
NOTES 1 L'eau de mer peut être analysée en modifiant la sensibilité et en adaptant la solution vecteur et les solutions d'étalonnage à la teneur en sel de l'échantillon. 2 Les termes suivants sont utilisés dans la présente Norme internationale:
nitrite(N): azote nitreux (concentration en masse)
nitrate(N): azote nitrique (concentration en masse)
nitrite/nitrate(N): somme de l'azote nitreux et de l'azote nitrique (concentration en masse)
Kakovost vode - Določevanje nitritnega in nitratnega dušika in vsota obeh s pretočno analizo (CFA in FIA) in spektrofotometrijsko detekcijo (ISO 13395:1996)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 13395:1999
01-marec-1999
.DNRYRVWYRGH'RORþHYDQMHQLWULWQHJDLQQLWUDWQHJDGXãLNDLQYVRWDREHKV
SUHWRþQRDQDOL]R &)$LQ),$ LQVSHNWURIRWRPHWULMVNRGHWHNFLMR ,62
Water quality - Determination of nitrite nitrogen and nitrate nitrogen and the sum of both
by flow analysis (CFA and FIA) and spectrometric detection (ISO 13395:1996)
Wasserbeschaffenheit - Bestimmung von Nitritstickstoff, Nitratstickstoff und der Summe
von beiden mit der Fließanalytik (CFA und FIA) und spektrometrischer Detektion (ISO
13395:1996)
Qualité de l'eau - Détermination de l'azote nitreux et de l'azote nitrique et de la somme
des deux par analyse en flux (CFA et FIA) et détection spectrométrique (ISO
13395:1996)
Ta slovenski standard je istoveten z: EN ISO 13395:1996
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
SIST EN ISO 13395:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 13395:1999
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SIST EN ISO 13395:1999
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SIST EN ISO 13395:1999
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SIST EN ISO 13395:1999
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SIST EN ISO 13395:1999
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SIST EN ISO 13395:1999
INTERNATIONAL IS0
STANDARD 13395
First edition
1996-07-15
Water quality - Determination of nitrite
nitrogen and nitrate nitrogen and the sum
of both by flow analysis (CFA and FIA) and
spectrometric detection
- Dbtermination de I ’azote nitreux et de I ’azote nitrique
Qua/it& de I ’eau
et de la somme des deux par analyse en flux (CFA et F/A) et dbtection
spectromktrique
Reference number
IS0 13395:1996(E)
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SIST EN ISO 13395:1999
IS0 13395:1996(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
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. IS0
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 International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 13395 was prepared by Technical Committee
lSO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical,
biochemical methods.
Annexes A, B, C and D of this International Standard are for information
only.
0 IS0 1996
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 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
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SIST EN ISO 13395:1999
0 IS0
IS0 13395:1996(E)
llntroduction
Methods using flow analysis enable wet chemistry procedures to be
automatized and are particularly suitable for the processing of many
analytes in water in large series of samples at a high analysis frequency
(up to 100 s amples per hour).
A differentiation is made between flow injection analysis (FIA) [I][*] and
continuous flow analysis (CFA) [31. Both methods share the feature of an
automatic dosage of the sample into a flow system (manifold) where the
analytes in the sample will 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 (e.g. flow
photometer).
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SIST EN ISO 13395:1999
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SIST EN ISO 13395:1999
IS0 13395:1996(E)
INTERNATIONAL STANDARD 0 ISo
etermination of nitrite nitrogen and
nd the sum of both by flow analysis
rometric detection
IS0 3696: 1987, Water for analytical laboratory use -
1 scope
Specification and test methods.
This International Standard specifies a method for the
IS0 5667-l :I 980, Water quality - Sampling -
determination of nitrite(N) (see note 2), nitrate(N) or
Part I: Guidance on the design of sampling pro-
the sum of both [nitrite/nitrate(N)], in various types
grammes.
of waters (such as ground, drinking, surface, and
waste waters) in mass concentrations ranging from
IS0 5667-2:1991, Water quality - Sampling -
0,Ol mg/l to 1 mg/l for nitrite(N) and from 0,2 mg/l to
Part 2: Guidance on sampling techniques.
20 mg/l for nitrite/nitrate(N), both in the undiluted
sample. The range of application can be changed by
IS0 5667-3:1994, Water quality - Sampling -
varying the operating conditions.
Part 3: Guidance on the preservation and handling of
samples.
NOTES
1 Seawater may be analysed with changes in respect to IS0 6777:1984, Water quality - Determination of ni-
sensitivity and adaptation of the carrier solution and cali-
trite - Molecular absorption spectrometrk method.
bration solutions to the salinity of the samples.
2 The following concise terms are used in the text of this
International Standard: 3 Principle
nitrite(N): (mass concentration of) nitrite,
expressed as nitrogen
3.1 Sum of nitrite(N) and nitrate(N),
nitrate(N): (mass concentration of) nitrate,
nitrite/nitrate(N)
expressed as nitrogen
nitrite,/nitrate(N): (mass concentration of) the sum
With flow injection analysis (FIA), the sample is fed
of nitrite(N) and nitrate(N)
into a continuously flowing buffer solution (carrier
stream) by means of an injection valve, or, with con-
tinuous flow analysis (CFA) being applied, it is con-
2 Normative references
tinuously mixed with this buffer solution. Nitrate in the
sample is reduced with metallic cadmium to
The following standards contain provisions which,
nitrite [4]. Then, a phosphoric acid reagent solution
through reference in this text, constitute provisions
that is also flowing continuously is admixed. Nitrite
of this International Standard. At the time of publi-
that is initially present and nitrite resulting from the
cation, the editions indicated were valid. All standards
reduction of nitrate will diazotize sulfanilamide in acid
are subject to revision, and parties to agreements
solution to the diazonium salt which is then coupled
based on this International Standard are encouraged
with A/-(I-naphthyI)ethylenediamine to form a red dye
to investigate the possibility of applying the most re-
[.51 [6lE71
.
cent editions of the standards indicated below.
Members of IEC and IS0 maintain registers of cur- Waste containing cadmium in liquid or solid form shall
be removed appropriately.
rently valid International Standards.
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SIST EN ISO 13395:1999
@a IS0
IS0 13395:1996(E)
4.11 Polyethyleneglycol dodecyl ether
3.2 Nitrite(N)
surfactant,
L-HO - p-p+* - O), - C,*&]r
8 = 33 “C to 41 “C, solution, w = 30 %.
Nitrite(N) is determined, omitting the cadmium re-
duction, directly by the above-mentioned diazotization
The solution is stable for approximately 4 weeks.
and coupling reaction 181. The chemical reactions of
the nitrite are identical with those in the manual pro-
cedure (see IS0 6777).
4.12 Cadmium granulate (Cd), grain size, for
example 0,3 mm to I,5 mm (a minimum reduction
3.3 Nitrate(N)
capacity of 90 % shall be reached; see 5.1 and 5.2).
The mass concentration of nitrate(N) is given by the
difference: nitrite/nitrate(N) - nitrite(N).
4.13 lmidazole stock solution, c = 0,25 mol/l.
4 Reagents
Dissolve, in a beaker of nominal capacity 1 litre,
17,0 g of imidazole (4.6) in approximately 900 ml of
If not stated otherwise, only reagents of recognized
water.
analytical grade and water according to grade 1 of
IS0 3696 shall be used. The blank value of the re-
While stirring with a magnetic stirrer, add hydrochloric
agents shall be checked regularly (see 9.3).
acid I (4.7) and adjust, with the help of a pH electrode,
the pH to 7.5.
4.1 Phosphoric acid (H,PO,), p = I,71 g/ml.
Transfer to a volumetric flask, of nominal capacity
1 000 ml, and dilute to volume with water.
4.2 Sulfanilamide (4aminobenzenesulfonamide,
The solution is stable for 4 weeks if kept in a brown
C,H,N,O,S).
glass bottle at room temperature.
4.3 N-( I-naphthyl)ethylenediaminedihydrochloride
[/V-(1 -naphthyl)-1,2-diaminoethanedihydrochloride),
4.14 Buffer solution.
W-MW21~
Mix 100 ml of the imidazole stock solution (4.13) with
100 j.~l of copper sulfate solution I (4.9).
4.4 Sodium nitrite (NaNO,), dried to constant mass
at, for example, 150 “C.
Prepare the solution freshly before use.
NOTE 3 Alternatively an ammonium buffer solution can
4.5 Potassium nitrate (KNO,), dried to constant
be used, for example:
mass at, for example, 150 “C.
85 g of ammonium chloride (NH&I) should be dissolved in
water and diluted to a volume of 1 000 ml, and the pH
4.6 lmidazole (C,H,N,), for synthesis, or alterna-
should be adjusted to approximately 7,5.
tively ammonium chloride (NH&I), dried to constant
mass at 105 “C (see note 3).
4.15 Carrier or dilution solutions, C and B in fig-
4.7 Hydrochloric acid I (HCI) concentrated,
ures A.1, B.l and C.1.
w = 37 %.
Table 1 shows some well-known options for preparing
these solutions.
4.8 Hydrochloric acid II, c(HCI) = 1 mol/l.
Prepare the solutions, containing the surfactant
4.9 Copper sulfate solution I,
(4.1 I), freshly before use.
p(CuSO,m5H,O) = 2,5 g/l; this solution is stable.
Prior to use, solutions C and B for FIA shall be
degassed, for example by membrane filtration (vac-
4.10 Copper sulfate solution II,
uum).
p(CuSO,m5H,O) = 20 g/l; this solution is stable.
2
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SIST EN ISO 13395:1999
0 IS0
IS0 13395:1996(E)
also be made separately and dosed into the equipment by
different lines.
Table 1 - Options for preparing the solutions C
and B in figures A.l, B.l and C.l
Prior to use, solution RI for FIA shall be degassed, for
example by membrane filtration (vacuum).
4.18 Nitrite(N) stock solution, pN = 100 mg/l.
Dissolve 492,6 mg of sodium nitrite (4.4) in water, in
a volumetric flask of nominal capacity 1 000 ml, and
dilute to volume.
This solution is stable for at least 2 weeks if kept in
a stoppered glass bottle at 4 “C.
4.18 Nitrite(N) solution I, pN = 20 mg/l.
Pipette 20 ml of the stock solution (4.18) into a
volumetric flask of nominal capacity 100 ml, and dilute
to volume with water.
Prepare the solution freshly before use.
4.20 Nitrite(N) solution II, PN = 1 mg/l.
1) Three different alternatives.
2) If, in the case of CFA, water or buffer (4.14) is used
Pipette 1 ml of the stock solution (4.18) into a
as solution B and 1 ml of surfactant (4.11) per 1 litre of
volumetric flask of nominal capacity 100 ml, and dilute
solution is added. If solution B is omitted, the surfactant
to volume with water.
(4.11) has to be added to the reagent solution RI (4.17,
see figures A.?, B.l and C.1).
Prepare the solution freshly before use.
4.21 Nitrate(N) solution I, PN = 200 mg/l.
4.16 Buffered copper sulfate solution.
Dissolve 144,4 mg of potassium nitrate (4.5) in water,
in a volumetric flask of nominal capacity 100 ml, and
Mix 20 ml of the copper sulfate solution II (4.10) and
dilute to volume.
20 ml of the imidazole stock solution (4.13) in a
beaker of nominal capacity 50 ml.
The solution is stable for at least 1 month.
Prepare the solution freshly before use.
4.22 Nitrate(N) solution II, PN = 20 mg/l.
Pipette 10 ml of the nitrate solution I (4.21) into a
4.17 Reagent solution, RI (in figures A.1, B.l and
volumetric flask of nominal capacity 100 ml, and dilute
. .
c 11
to volume with water.
Dissolve, in a volumetric flask of nominal capacity
Prepare the solution freshly before use.
500 ml, 5 g of sulfanilamide (4.2), 0,5 g of
A/-(I-naphthyl)ethylenediaminedihydrochloride (4.3) in
4.23 Calibration solutions
water, add 50 ml of phosphoric acid (4.1), and dilute
to volume.
The calibration solutions are prepared by diluting the
respective solutions described in 4.19 to 4.22. These
Stored in a brown glass bottle, the solution is stable
solutions may be used in any combination for the
for at least one week.
preparation of calibration solutions for the determi-
nation of nitrite(N), nitrite/nitrate(N) or nitrate(N). At
NOTE 4 For the preparation of this reagent solution,
least five calibration standards per working range are
hydrochloric acid (4.7, 4.8) may be used instead of
phosphoric acid, provided equivalent performance charac- recommended.
teristics are obtained. The solutions of sulfanilamide (4.2)
and N-(1 -naphthyl)ethylenediaminedihydrochloride (4.3) can The following working ranges are provided:
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SIST EN ISO 13395:1999
0 IS0
IS0 13395:1996(E)
Proceed, for example, as recommended in tables 2
For nitrite(N): Working range II:
and 3 (if 10 standards are used).
0,Ol mg/l to 0,l mg/l
Working range I: 0,l mg/l
All calibration solutions shall be prepared immediately
to I,0 mg/l
before measurement.
For nitrite/nitrate(N): Working range II:
0,2 mg/l to 2 mg/l
Working range I: 2 mg/l to
20 mg/l
- Preparation of the calibration solutions for nitrite(N)
Table 2
Volume of nitrite(N) Volume of nitrite(N)
solution II (4.20) Nitrite(N) solution I (4.19)
Nitrite(N) concentration
diluted with water concentration diluted with water
to 100 ml to 200 ml
ml ml
n-al
0,Ol I 011 1
0,02 2 02 2
0,03 3 013 3
0,04 4 4
09
0,05 5 5
015
I I I I
6 6
0,06 0,6
I I I I
0,08 8 8
03
I I I I
9 9
0,09 03
I I I
10
OJO 10
LO
I I
- Preparation of the calibration solutions for nitrite/nitrate(N)
Table 3
Volume of nitrate(N) Volume of
solution II (4.22) Nitrate(N) nitrate(N) solution I
Nitrate(N) concentration
diluted with water concentration (4.21) diluted with
to 100 ml water to 100 ml
ml ml
w/l w/l
1 2 1
02
2 4 2
a4
I I
3 6 3
05
I I
4 8 4
W3
I
5 10
5
LO
I I
6 12 6
12
I I
14
7
8
16 8
15
I I I
9 18
9
13
I I
10
20 IO
zo
I I 1
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SIST EN ISO 13395:1999
0 IS0 IS0 13395:1996(E)
- If nitrite/nitrate(N) or nitrate(N) is to be determined:
5 Apparatus
cadmium reductor with a minimum reduction ef-
ficiency of 90 %, e.g. cadmium tube [IO] of internal
Usual laboratory apparatus and
diameter 1 ,I mm or cadmium column (see 5.1).
- Manifold with highly reproducible gas-bubble
5.1 Flow injection system (FIA), normally compris-
feeding (nitrogen is recommended), sample and
ing the following components (see figure A.1).
reagent feeding, with appropriate transport sys-
tems and connection assemblies of chemically
- Reagent reservoirs.
inert plastics or metal. The application of the cad-
mium reductor requires oxygen-free gas. Before
-- Low pulsation pump.
entering the cadmium column the flow stream has
to be debubbled, if air is used for segmenting the
- Suitable pump tubing, if required.
flow stream.
- Sample injector with an injection volume of IO pi
- Dialysis cell, if required, with, for example, a
to 300 pi.
cellulose membrane, suitable for the predilution
of the sample or the elimination of interfering
- if nitrite/nitrate(N) or nitrate(N) is to be determined:
compounds.
cadmium reductor with a minimum reduction ef-
ficiency of 90 %, e.g. packed cadmium column
- Photometric detector with flow ceil, wavelength
(4.12), of internal diameter
with granulate
range 520 nm to 560 nm.
4,0 mm, for example, and minimum length 5 cm.
- Recording unit (e.g. strip chart recorder, integrator
- Transport tubes and reaction coils of internal di-
or printer/plotter). in general, peak height signals
ameter 0,5 mm to 0,8 mm, with tube connections
are evaluated.
and T-connections of chemically inert plastics.
NOTE 6 Figure B.l describes two flow systems with
- Dialysis cell, if required, with, for example, a
an internal diameter of approximately 1. mm. Figure Cl
cellulose membrane, suitable for the prediiution
shows a flow system (for the determination of
of the sample or the elimination of interfering
nitrite/nitrate(N) with an internal diameter of 2,2 mm.
compounds.
5.3 Volumetric flasks, of nominal capacity 100 ml,
NOTE 5 The dialysis cell should be placed after the
500 ml and 1 000 ml.
injector (see figureA.l). The carrier solution C may serve
as a donor and also as a recipient solution. The flow
rates of these two streams should be equal.
5.4 Pipettes, of nominal capacity 100 ~1, 1 ml to
10 ml, 20 ml, 50 ml and 100 ml.
- Photometric detector with flow cell, wavelength
range 520 nm to 560 nm.
5.5 Beakers, of nominal capacity 25 ml, 50 ml and
1 Iitre.
- Recording unit (e.g. strip chart recorder, integrator
or printer/plotter). in general, peak height signals
5.6 Syringe, of nominal capacity 25 ml.
are evaluated.
- Autosampler, if required.
5.7 Membrane filter assembly, with membrane fil-
ters of pore size 0,45 pm.
5.2 Continuous flow analysis (CFA), normally
5.8 pH electrode.
components (see
comprising the following
figure B. I ):
6 Checking the flow system
allowing a repro-
- Autosampler or any other device
A calibration solution (4.23) with a nitrite(N) concen-
ducible application of the sample.
tration of 0,05 mg/l, or a nitrate(N) concentration of
1 mg/l, measured in the system (FIA or CFA,
- Reagent reservoirs.
respectively) which is adjusted to the lower working
range, should give an absorbance of at least 0,04 per
- Low pulsation pump with suitable, chemically inert
10 mm path length.
pump tubes.
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SIST EN ISO 13395:1999
63 IS0
IS0 13395:1996(E)
NOTE 7 If the photometric detector (see 5.1 or 5.2) does
nitrate mass concentration in the sample can be ruled
not give any absorbance readings, the absorbance may then
out.
be determined by comparing with an external absorbance-
measuring photometer.
The self-absorption of the sample can be compen-
sated by measuring, in addition to the sample signal
(9.5) the signal of the sample without the admixture
7 Sampling and sample preparation of the reagents. In this case, the difference of the two
responses is used for the evaluation (according to
Before use, all containers coming into contact with clause IO).
the sample shall be cleaned thoroughly with water
Prior to the measurement, dilute samples with a total
and shall be rinsed several times with the samples.
salt concentration of > 30 g/l.
(See IS0 5667-3.)
If only nitrite is to be determined, collect the sample
8.2 interference with the reduction of nitrate
in a glass or polyethylene bottle and analyse it at
to nitrite
once. Proceed in the same way, if nitrate is to be de-
termined and if the nitrite(N) concentration is at least
Interferences may occur if the sample, after the ad-
in the same working range as the nitrate(N) concen-
mixture of the buffer solution, does not reach a pH
tration.
of 6,5 to 7,5. This may happen with strongly acid,
basic or buffered samples. In this event, the sample
If only nitrite/nitrate(N) is to be determined, or
shall, prior to the measurement, be treated appropri-
nitrate(N) in samples with nitrite(N) concentrations
ately with bases or acids so as to re
...
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