SIST ISO 17378-2:2019
Water quality - Determination of arsenic and antimony - Part 2: Method using hydride generation atomic absorption spectrometry (HG-AAS)
Water quality - Determination of arsenic and antimony - Part 2: Method using hydride generation atomic absorption spectrometry (HG-AAS)
This part of ISO 17378 specifies a method for the determination of arsenic and antimony. The method
is applicable to drinking water, surface water, ground water, and rain water. The approximate linear
application range of this part of ISO 17378 for both elements is from 0,5 μg/l to 20 μg/l. Samples
containing higher concentrations than the application range can be analysed following appropriate
dilution.
Generally sea water is outside the scope of this part of ISO 17378. Sea water samples can be analysed
using a standard additions approach providing that this is validated for the samples under test. The
method is unlikely to detect organo-arsenic and organo-antimony compounds.
The sensitivity of this method is dependent on the selected operating conditions.
Qualité de l'eau - Dosage de l'arsenic et de l'antimoine - Partie 2: Méthode par spectrométrie d'absorption atomique à génération d'hydrures (HG-AAS)
L'ISO 17378-2:2014 sp�cifie une m�thode pour le dosage de l'arsenic et de l'antimoine. Cette m�thode s'applique � l'eau potable, aux eaux de surface, aux eaux souterraines et � l'eau de pluie. La plage d'application lin�aire de l'ISO 17378-2:2014 s'�tend de 0,5 �g/l � 20 �g/l. Les �chantillons contenant de l'arsenic ou de l'antimoine dans des concentrations plus �lev�es que la plage d'application peuvent �tre analys�s apr�s une dilution appropri�e.
L'eau de mer n'entre g�n�ralement pas dans le domaine d'application de l'ISO 17378-2:2014. Les �chantillons d'eau de mer peuvent �tre analys�s � l'aide d'une technique de l'ajout dos� dans la mesure o� celle-ci a �t� valid�e pour les �chantillons soumis � essai. Il est peu probable que cette m�thode d�tecte des compos�s organoars�ni�s et organoantimoni�s.
La sensibilit� de cette m�thode d�pend des conditions op�ratoires choisies.
Kakovost vode - Določevanje arzena in antimona - 2. del: Atomska absorpcijska spektrometrijska metoda s hidridno tehniko (HG-AAS)
Ta del standarda ISO 17378 opredeljuje metodo za določevanje arzena in antimona. Metoda se uporablja za pitno in površinsko vodo, podtalnico in deževnico. Približno območje linearne uporabe tega dela standarda ISO 17378 za oba elementa je od 0,5 μg/l do 20 μg/l. Vzorce z višjimi koncentracijami od obsega uporabe je mogoče analizirati po ustreznem redčenju.
Morska voda na splošno ne spada na področje uporabe tega dela standarda ISO 17378. Vzorce morske vode je mogoče analizirati s standardnim pristopom dodajanja, če je potrjen za vzorce, ki se preskušajo. Z
metodo je zaznavanje organsko-arzenovih in organsko-antimonovih spojin malo verjetno.
Občutljivost te metode je odvisna od izbranih delovnih razmer.
General Information
Buy Standard
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 17378-2
First edition
2014-02-01
Water quality — Determination of
arsenic and antimony —
Part 2:
Method using hydride generation
atomic absorption spectrometry (HG-
AAS)
Qualité de l’eau — Dosage de l’arsenic et de l’antimoine —
Partie 2: Méthode par spectrométrie d’absorption atomique à
génération d’hydrures (HG-AAS)
Reference number
ISO 17378-2:2014(E)
©
ISO 2014
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ISO 17378-2:2014(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
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ISO copyright office
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
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Published in Switzerland
ii © ISO 2014 – All rights reserved
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ISO 17378-2:2014(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Principle . 2
3.1 Arsenic . 2
3.2 Antimony . 2
4 Interferences . 2
4.1 General . 2
4.2 Arsenic . 3
4.3 Antimony . 3
5 Reagents . 3
5.1 General requirements . 3
6 Apparatus . 8
7 Sampling and sample preparation . 9
7.1 Sampling technique . 9
7.2 Pre-reduction . 9
8 Instrumental set up .10
9 Procedure.10
9.1 General requirements .10
9.2 Analysis using the method of standard calibration .11
9.3 Analysis using the standard addition method of calibration .11
10 Calibration and data analysis .12
10.1 General requirements .12
10.2 Calculation using the calibration curve .12
10.3 Calculation using the standard addition method .13
11 Expression of results .13
12 Test report .13
Annex A (informative) Additional information .14
Annex B (informative) Schematic flow diagram and signal response .15
Annex C (informative) Example of enrichment technique .17
Annex D (informative) Performance data .19
Bibliography .22
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ISO 17378-2:2014(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 (see 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 (see 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.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
This first edition of ISO 17378-2 cancels and replaces ISO 11969:1996, which has been technically
revised.
ISO 17378 consists of the following parts, under the general title Water quality — Determination of
arsenic and antimony:
— Part 1: Method using hydride generation atomic fluorescence spectrometry (HG–AFS)
— Part 2: Method using hydride generation atomic absorption spectrometry (HG–AAS)
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ISO 17378-2:2014(E)
Introduction
This part of ISO 17378 should be used by analysts experienced in the handling of trace elements at very
low concentrations.
Arsenic concentrations in natural waters are highly variable, from <10 μg/l to as high as several
milligrams per litre in some parts of Asia, South America and the USA, notable in the Ganges delta
where arsenic poisoning from contaminated tube wells is a serious problem. Antimony concentrations
in natural waters are generally well below 10 μg/l. Arsenic and antimony occur naturally in organic and
inorganic compounds and may have oxidation states −III, 0, III and V.
In order to fully decompose all of the arsenic or antimony compounds, a digestion procedure is necessary.
Digestion can only be omitted if it is certain that the arsenic or antimony in the sample can form a
covalent hydride without the necessity of a pre-oxidation step.
The user should be aware that particular problems could require the specification of additional marginal
conditions.
The method for determining arsenic or antimony is identical in all aspects except for the preparation
of standard solutions to be tested. To avoid repetition or duplication the text refers to both arsenic and
antimony where the text is equally applicable to both instances. The subclause dealing with preparation
of standard solutions is divided into 5.11.1, which deals with solutions of arsenic, and 5.11.2, which deals
with solutions of antimony.
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INTERNATIONAL STANDARD ISO 17378-2:2014(E)
Water quality — Determination of arsenic and antimony —
Part 2:
Method using hydride generation atomic absorption
spectrometry (HG-AAS)
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document 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 according to this document be
carried out by suitably trained and experienced staff.
1 Scope
This part of ISO 17378 specifies a method for the determination of arsenic and antimony. The method
is applicable to drinking water, surface water, ground water, and rain water. The approximate linear
application range of this part of ISO 17378 for both elements is from 0,5 µg/l to 20 µg/l. Samples
containing higher concentrations than the application range can be analysed following appropriate
dilution.
Generally sea water is outside the scope of this part of ISO 17378. Sea water samples can be analysed
using a standard additions approach providing that this is validated for the samples under test. The
method is unlikely to detect organo-arsenic and organo-antimony compounds.
The sensitivity of this method is dependent on the selected operating conditions.
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 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 5667-5, Water quality — Sampling — Part 5: Guidance on sampling of drinking water from treatment
works and piped distribution systems
ISO 5667-6, Water quality — Sampling — Part 6: Guidance on sampling of rivers and streams
ISO 5667-8, Water quality — Sampling — Part 8: Guidance on the sampling of wet deposition
ISO 5667-11, Water quality — Sampling — Part 11: Guidance on sampling of groundwaters
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
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ISO 17378-2:2014(E)
ISO 15587-1, Water quality — Digestion for the determination of selected elements in water — Part 1: Aqua
regia digestion
3 Principle
NOTE Other measurement techniques can be applicable providing the performance criteria are adequately
demonstrated to be fulfilled or exceeded by the user laboratory. (See Annex C.)
3.1 Arsenic
An aliquot of sample is acidified with hydrochloric acid (5.3). Potassium iodide–ascorbic acid reagent
(5.9) is added to ensure quantified reduction of arsenic(V) to arsenic(III). The sample solutions are
treated with sodium tetrahydroborate (5.5) to generate the covalent gaseous arsenic trihydride (arsine,
AsH ). The hydride and excess hydrogen are swept out of the generation vessel in case of batch mode and
3
out of the gas/liquid separator in case of the continuous mode into a heated silica cell. After atomization,
the absorbance of arsenic is determined at a wavelength λ = 193,7 nm. The procedure is automated by
means of auto-sampler and control software.
3.2 Antimony
An aliquot of sample is digested with hydrochloric acid (5.3). Potassium iodide–ascorbic acid reagent
(5.9) is added to ensure quantified reduction of the antimony(V) to antimony(III). The sample solutions
are then treated with sodium tetrahydroborate (5.5) to generate the covalent gaseous antimony
trihydride (stibane, SbH ). The hydride and excess hydrogen are swept out of the generation vessel in
3
case of batch mode and out of the gas/liquid separator in case of continuous mode. After atomization,
the absorbance of antimony is determined at a wavelength λ = 217,6 nm. The procedure is automated by
means of auto-sampler and control software.
4 Interferences
4.1 General
The hydride generation technique is prone to interferences by transition and easily reducible metals.
For the majority of natural water samples, this type of interference shall not be significant. The user
should carry out recovery tests on typical waters and also determine the maximum concentrations of
potentially interfering elements, using appropriate methods. If such interferences are indicated, the
level of interferences should be assessed by performing spike recoveries.
Metals which are readily reduced by sodium tetrahydroborate may also cause interferences. In particular,
these include chromium, iron, copper, nickel, and lead. If the concentrations of these elements specified
in Table 1 are exceeded, a significant decrease of absorption may occur.
Table 1 — Maximum mass concentration in test solution of interfering heavy metals
(valid for flow systems)
Interfering element
Cr Fe Cu Ni Pb
mg/l
500 500 500 250 100
The reaction conditions in this part of ISO 17378 have been chosen to minimize these interferences.
[1][2]
Further information on these interferences and the technique are given in References.
NOTE If batch systems are used, mass concentrations which are appreciably lower than those specified in
Table 1, Table 2 and Table 3 can cause interferences.
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ISO 17378-2:2014(E)
4.2 Arsenic
Elements such as antimony, selenium, tellurium, mercury, and tin are also volatilized by this procedure
and may cause interferences. These elements do not cause interferences providing the concentrations
specified in Table 2 are not exceeded.
Table 2 — Maximum mass concentration of hydride-forming or volatile elements causing no
interferences
Element
Sb Se Sn Te Hg
mg/l
1 1 0,1 1 0,1
If these concentrations are exceeded, it may be necessary to use the standard addition method (9.3).
Assuming that the arsenic content is high enough, an appropriate dilution of the water sample is
preferred.
4.3 Antimony
Elements such as arsenic, selenium, tellurium, mercury, and tin are also volatilized by this procedure
and may cause interferences. These elements do not cause interferences providing the concentrations
specified in Table 3 are not exceeded.
Table 3 — Maximum mass concentration of hydride-forming or volatile elements causing no
interferences
Element
As Se Sn Te Hg
mg/l
1 1 0,1 1 0,1
If these concentrations are exceeded, it may be necessary to use the standard addition method (9.3).
Assuming that the antimony content is high enough, an appropriate dilution of the water sample is
preferred.
5 Reagents
5.1 General requirements
It is important to use high purity reagents in all cases with minimum levels of arsenic or antimony.
Reagents may contain arsenic or antimony as an impurity. All reagents shall have arsenic or antimony
concentrations below that which would result in an arsenic or antimony blank value for the method
being above the lowest level of interest.
Use only reagents of recognized analytical grade, unless otherwise specified.
Reagents shall be prepared to manufacturer’s recommendations using the following series as an example.
5.2 Water, complying with grade 1 as defined in ISO 3696, for all sample preparation and dilutions.
5.3 Hydrochloric acid, ρ(HCl) = 1,16 g/ml.
5.4 Hydrochloric acid, c(HCl) = 1 mol/l.
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ISO 17378-2:2014(E)
5.5 Sodium tetrahydroborate, NaBH .
4
Available as pellets. Keep the pellets dry and store in a cool, dark place.
5.6 Sodium hydroxide, NaOH.
5.7 Sodium tetrahydroborate solution, ρ(NaBH ) = 13 g/l.
4
Prepare appropriate quantities on day of use (13 g/l has proven suitable for the system illustrated in
Figure B.1).
Dissolve 0,4 g sodium hydroxide (5.6) and the appropriate quantity of sodium tetrahydroborate (5.5) in
800 ml of water and dilute to 1 000 ml.
Do not keep in a closed container because of potential pressure build-up due to hydrogen evolution.
Excess sodium borohydride solution should be slowly poured to drain with copious quantities of water.
Do not allow the solution to come into contact with acid during disposal.
NOTE The concentration of NaBH is dependent on the hybride generator manifold and flow-rate conditions.
4
See recommendations of the manufacturer.
Alternatively smaller volumes can be prepared on a pro rata basis.
5.8 Nitric acid, ρ(HNO ) = 1,40 g/ml.
3
NOTE Nitric acid is available both as ρ(HNO ) = 1,40 g/ml [w(HNO ) = 650 g/kg] and ρ(HNO ) = 1,42 g/ml
3 3 3
[w(HNO ) = 690 g/kg].
3
To prepare a nitric acid cleaning mixture, dilute nitric acid (1,40 g/ml) with an equal volume of water
(5.2) by carefully adding the acid to the water.
5.9 Potassium iodide–ascorbic acid solution.
Dissolve (250 ± 0,1) g of potassium iodide (KI) and (50 ± 0,1) g of ascorbic acid (C H O ) in approximately
6 8 6
400 ml water and dilute to 500 ml.
Prepare freshly on day of use. See Note to (5.7).
5.10 Reagent blank.
For each 1 000 ml, prepare a solution containing (300 ± 3) ml of hydrochloric acid (5.3) and (20 ± 0,5) ml
of potassium iodide–ascorbic acid solution (5.9). Dilute to volume with water (5.2).
IMPORTANT — On the continuous flow system, the reagent blank solution is run as background.
Since the blank solution can contain trace level detectable amounts of arsenic or antimony,
ensure that the same reagents are used for both sample and standard preparation as well as for
the preparation of the reagent blank.
The analyte signal is superimposed on the top of this signal once the sample is introduced into the
measurement cycle. Arsenic and antimony concentrations in the reagent blank solution should be less
than the lower levels of interest.
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ISO 17378-2:2014(E)
5.11 Standard solutions (arsenic and antimony).
5.11.1 Arsenic solutions (standard, stock and calibration).
5.11.1.1 Arsenic stock solution A, ρ[As(III)] = 1 000 mg/l.
Use a quantitative stock solution with an arsenic(III) content of (1 000 ± 2) mg/l.
This solution is considered to be stable for at least one year.
NOTE If other stock solutions are available, they can be used providing the uncertainty of the measurement
is not compromised.
Alternatively, use a stock solution prepared from high purity grade chemicals:
Place (1,734 ± 0,002) g of sodium metaarsenite NaAsO in a 1 000 ml volumetric flask.
2
Add (50 ± 0,5) ml of hydrochloric acid (5.3) and dissolve the sodium metaarsenite completely by stirring.
Dilute to 1 l with water (5.2).
5.11.1.2 Arsenic standard solution B, ρ[As(III)] = 10 mg/l.
Pipette (1 ± 0,01) ml of arsenic stock solution A (5.11.1.1) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one month.
5.11.1.3 Arsenic standard solution C, ρ[As(III)] = 100 µg/l.
Pipette (1 ± 0,01) ml of arsenic standard solution B (5.11.1.2) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one week.
5.11.1.4 Arsenic stock solution D, ρ[As(V)] = 1 000 mg/l.
Dissolve (1,000 ± 0,002) g of pure arsenic powder in (10 ± 0,1) ml of concentrated nitric acid (5.8).
Heat the solution to boiling and evaporate off the excess nitric acid.
Perform this procedure carefully under a chemical hood.
Cool and then take up the hydrated arsenic(V) oxide in (50 ± 0,5) ml of cold hydrochloric acid (5.3).
Transfer the solution quantitatively to a 1 000 ml volumetric flask and fill up to the mark with water
(5.2).
This standard shall be used to prepare a suitable arsenic(V) standard to check quantitative recovery of
arsenic(V). Should the presence of arsenic(V) in the samples be suspected, use this standard to check
recovery of this analyte.
The solution is stable for at least six months.
NOTE If other stock solutions are available, they can be used providing the uncertainty of the measurement
is not compromised.
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ISO 17378-2:2014(E)
5.11.1.5 Arsenic calibration solutions.
Use a minimum of five independent calibration solutions. Carry out the calibration as specified in
ISO 8466-1.
Prepare a minimum of five arsenic calibration solutions from the arsenic standard solution C (5.11.1.3)
covering the working range of expected arsenic concentrations.
For the operating range from 1 µg/l to 5 µg/l, for example, proceed e.g. as follows:
Pipette into a series of five 100 ml volumetric flasks (1 ± 0,01) ml, (2 ± 0,02) ml, (3 ± 0,03) ml, (4 ±
0,04) ml and (5 ± 0,05) ml, respectively, of arsenic standard solution C (5.11.1.3).
Add 30 ml of hydrochloric acid (5.3) and 2 ml of potassium iodide–ascorbic acid solution (5.9).
Dilute to 100 ml with water (5.2) and mix thoroughly.
Allow to stand for at least 2 h before using to ensure quantitative reduction of arsenic(V) to arsenic(III).
These calibration solutions contain 1 µg/l, 2 µg/l, 3 µg/l, 4 µg/l and 5 µg/l arsenic respectively.
They shall be prepared on the day of use.
The use of piston pipettes is permitted and enables the preparation of lower volumes of calibration
solutions. The application of dilutors is also allowed.
Once an established calibration pattern has been confirmed, the number of standards used routinely
may be reduced. Any such change shall not alter the result obtained from tests or the ranking with other
samples.
5.11.2 Antimony solutions (standard, stock and calibration).
5.11.2.1 Antimony stock solution A, ρ[Sb(III)] = 1 000 mg/l.
Use a quantitative stock solution with an antimony(III) content of (1 000 ± 2) mg/l.
This solution is considered to be stable for at least one year.
Alternatively, use a stock solution prepared from high purity grade chemicals:
Place (2,743 ± 0,002) g of potassium antimony(III) oxide tartrate hemihydrate, K(SbO)C H O ∙0,5H O
4 4 6 2
in a 1 000 ml volumetric flask.
Add (50 ± 0,5) ml of hydrochloric acid (5.3) and dissolve the potassium antimony(III) oxide tartrate
hemihydrate by stirring.
Dilute to 1 l with water (5.2).
5.11.2.2 Antimony standard solution B, ρ[Sb(III)] = 10 mg/l.
Pipette (1 ± 0,01) ml of antimony stock solution A (5.11.2.1) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,01) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one week.
NOTE If a suitable commercial standard is available, it can be used if performance validated.
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ISO 17378-2:2014(E)
5.11.2.3 Antimony standard solution C, ρ[Sb(III)] = 100 µg/l.
Pipette (1 ± 0,01) ml of antimony standard solution B (5.11.2.2) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution shall be prepared weekly.
5.11.2.4 Antimony stock solution D, ρ[Sb(V)] = 1 000 mg/l.
Dissolve (1,000 ± 0,002) g of pure antimony powder in (10 ± 0,1) ml of concentrated nitric acid (5.8).
Heat the solution to boiling and evaporate off the excess nitric acid.
Perform this procedure carefully under a chemical hood.
Cool and then take up the hydrated antimony(V) oxide in (50 ± 0,5) ml of cold hydrochloric acid (5.3).
Transfer the solution quantitatively to a 1 000 ml volumetric flask and fill up to the mark with water
(5.2).
This standard should be used to prepare a suitable antimony(V) standard to check quantitative recovery
of antimony(V).
The solution is stable for at least six months.
Dilute antimony(V) standard solutions should be prepared on the day of use and checked for turbidity
which is evidence that hydrolysis has occurred. Discard any solution that exhibits any visible turbidity.
5.11.2.5 Antimony calibration solutions.
Use a minimum of five independent calibration solutions. Carry out the linear calibration as specified in
ISO 8466-1.
Prepare a minimum of five antimony calibration solutions from the antimony standard solution C
(5.11.2.3) covering the working range of expected antimony concentrations.
For example, for an operating range from 1 µg/l to 5 µg/l proceed as follows.
Pipette into a series of five 100 ml volumetric flasks (1 ± 0,01) ml, (2 ± 0,02) ml, (3 ± 0,03) ml, (4 ±
0,04) ml, and (5 ± 0,05) ml, respectively, of antimony standard solution C (5.11.2.3).
Add 30 ml of hydrochloric acid (5.3) and 2 ml of potassium iodide–ascorbic acid solution (5.9).
Dilute to 100 ml with water (5.2) and mix thoroughly.
Allow to stand for at least 2 h before using to ensure quantitative reduction of antimony(V) to
antimony(III).
These calibration solutions contain 1 µg/l, 2 µg/l, 3 µg/l, 4 µg/l, and 5 µg/l antimony, respectively.
They shall be prepared on the day of use.
The use of piston pipettes is permitted and enables the preparat
...
SLOVENSKI STANDARD
SIST ISO 17378-2:2019
01-oktober-2019
Kakovost vode - Določevanje arzena in antimona - 2. del: Atomska absorpcijska
spektrometrijska metoda s hidridno tehniko (HG-AAS)
Water quality - Determination of arsenic and antimony - Part 2: Method using hydride
generation atomic absorption spectrometry (HG-AAS)
Qualité de l'eau - Dosage de l'arsenic et de l'antimoine - Partie 2: Méthode par
spectrométrie d'absorption atomique à génération d'hydrures (HG-AAS)
Ta slovenski standard je istoveten z: ISO 17378-2:2014
ICS:
13.060.50 Preiskava vode na kemične Examination of water for
snovi chemical substances
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
SIST ISO 17378-2:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 17378-2:2019
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SIST ISO 17378-2:2019
INTERNATIONAL ISO
STANDARD 17378-2
First edition
2014-02-01
Water quality — Determination of
arsenic and antimony —
Part 2:
Method using hydride generation
atomic absorption spectrometry (HG-
AAS)
Qualité de l’eau — Dosage de l’arsenic et de l’antimoine —
Partie 2: Méthode par spectrométrie d’absorption atomique à
génération d’hydrures (HG-AAS)
Reference number
ISO 17378-2:2014(E)
©
ISO 2014
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SIST ISO 17378-2:2019
ISO 17378-2:2014(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
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ii © ISO 2014 – All rights reserved
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Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Principle . 2
3.1 Arsenic . 2
3.2 Antimony . 2
4 Interferences . 2
4.1 General . 2
4.2 Arsenic . 3
4.3 Antimony . 3
5 Reagents . 3
5.1 General requirements . 3
6 Apparatus . 8
7 Sampling and sample preparation . 9
7.1 Sampling technique . 9
7.2 Pre-reduction . 9
8 Instrumental set up .10
9 Procedure.10
9.1 General requirements .10
9.2 Analysis using the method of standard calibration .11
9.3 Analysis using the standard addition method of calibration .11
10 Calibration and data analysis .12
10.1 General requirements .12
10.2 Calculation using the calibration curve .12
10.3 Calculation using the standard addition method .13
11 Expression of results .13
12 Test report .13
Annex A (informative) Additional information .14
Annex B (informative) Schematic flow diagram and signal response .15
Annex C (informative) Example of enrichment technique .17
Annex D (informative) Performance data .19
Bibliography .22
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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 (see 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 (see 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.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
This first edition of ISO 17378-2 cancels and replaces ISO 11969:1996, which has been technically
revised.
ISO 17378 consists of the following parts, under the general title Water quality — Determination of
arsenic and antimony:
— Part 1: Method using hydride generation atomic fluorescence spectrometry (HG–AFS)
— Part 2: Method using hydride generation atomic absorption spectrometry (HG–AAS)
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Introduction
This part of ISO 17378 should be used by analysts experienced in the handling of trace elements at very
low concentrations.
Arsenic concentrations in natural waters are highly variable, from <10 μg/l to as high as several
milligrams per litre in some parts of Asia, South America and the USA, notable in the Ganges delta
where arsenic poisoning from contaminated tube wells is a serious problem. Antimony concentrations
in natural waters are generally well below 10 μg/l. Arsenic and antimony occur naturally in organic and
inorganic compounds and may have oxidation states −III, 0, III and V.
In order to fully decompose all of the arsenic or antimony compounds, a digestion procedure is necessary.
Digestion can only be omitted if it is certain that the arsenic or antimony in the sample can form a
covalent hydride without the necessity of a pre-oxidation step.
The user should be aware that particular problems could require the specification of additional marginal
conditions.
The method for determining arsenic or antimony is identical in all aspects except for the preparation
of standard solutions to be tested. To avoid repetition or duplication the text refers to both arsenic and
antimony where the text is equally applicable to both instances. The subclause dealing with preparation
of standard solutions is divided into 5.11.1, which deals with solutions of arsenic, and 5.11.2, which deals
with solutions of antimony.
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INTERNATIONAL STANDARD ISO 17378-2:2014(E)
Water quality — Determination of arsenic and antimony —
Part 2:
Method using hydride generation atomic absorption
spectrometry (HG-AAS)
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document 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 according to this document be
carried out by suitably trained and experienced staff.
1 Scope
This part of ISO 17378 specifies a method for the determination of arsenic and antimony. The method
is applicable to drinking water, surface water, ground water, and rain water. The approximate linear
application range of this part of ISO 17378 for both elements is from 0,5 µg/l to 20 µg/l. Samples
containing higher concentrations than the application range can be analysed following appropriate
dilution.
Generally sea water is outside the scope of this part of ISO 17378. Sea water samples can be analysed
using a standard additions approach providing that this is validated for the samples under test. The
method is unlikely to detect organo-arsenic and organo-antimony compounds.
The sensitivity of this method is dependent on the selected operating conditions.
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 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 5667-5, Water quality — Sampling — Part 5: Guidance on sampling of drinking water from treatment
works and piped distribution systems
ISO 5667-6, Water quality — Sampling — Part 6: Guidance on sampling of rivers and streams
ISO 5667-8, Water quality — Sampling — Part 8: Guidance on the sampling of wet deposition
ISO 5667-11, Water quality — Sampling — Part 11: Guidance on sampling of groundwaters
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
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ISO 15587-1, Water quality — Digestion for the determination of selected elements in water — Part 1: Aqua
regia digestion
3 Principle
NOTE Other measurement techniques can be applicable providing the performance criteria are adequately
demonstrated to be fulfilled or exceeded by the user laboratory. (See Annex C.)
3.1 Arsenic
An aliquot of sample is acidified with hydrochloric acid (5.3). Potassium iodide–ascorbic acid reagent
(5.9) is added to ensure quantified reduction of arsenic(V) to arsenic(III). The sample solutions are
treated with sodium tetrahydroborate (5.5) to generate the covalent gaseous arsenic trihydride (arsine,
AsH ). The hydride and excess hydrogen are swept out of the generation vessel in case of batch mode and
3
out of the gas/liquid separator in case of the continuous mode into a heated silica cell. After atomization,
the absorbance of arsenic is determined at a wavelength λ = 193,7 nm. The procedure is automated by
means of auto-sampler and control software.
3.2 Antimony
An aliquot of sample is digested with hydrochloric acid (5.3). Potassium iodide–ascorbic acid reagent
(5.9) is added to ensure quantified reduction of the antimony(V) to antimony(III). The sample solutions
are then treated with sodium tetrahydroborate (5.5) to generate the covalent gaseous antimony
trihydride (stibane, SbH ). The hydride and excess hydrogen are swept out of the generation vessel in
3
case of batch mode and out of the gas/liquid separator in case of continuous mode. After atomization,
the absorbance of antimony is determined at a wavelength λ = 217,6 nm. The procedure is automated by
means of auto-sampler and control software.
4 Interferences
4.1 General
The hydride generation technique is prone to interferences by transition and easily reducible metals.
For the majority of natural water samples, this type of interference shall not be significant. The user
should carry out recovery tests on typical waters and also determine the maximum concentrations of
potentially interfering elements, using appropriate methods. If such interferences are indicated, the
level of interferences should be assessed by performing spike recoveries.
Metals which are readily reduced by sodium tetrahydroborate may also cause interferences. In particular,
these include chromium, iron, copper, nickel, and lead. If the concentrations of these elements specified
in Table 1 are exceeded, a significant decrease of absorption may occur.
Table 1 — Maximum mass concentration in test solution of interfering heavy metals
(valid for flow systems)
Interfering element
Cr Fe Cu Ni Pb
mg/l
500 500 500 250 100
The reaction conditions in this part of ISO 17378 have been chosen to minimize these interferences.
[1][2]
Further information on these interferences and the technique are given in References.
NOTE If batch systems are used, mass concentrations which are appreciably lower than those specified in
Table 1, Table 2 and Table 3 can cause interferences.
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4.2 Arsenic
Elements such as antimony, selenium, tellurium, mercury, and tin are also volatilized by this procedure
and may cause interferences. These elements do not cause interferences providing the concentrations
specified in Table 2 are not exceeded.
Table 2 — Maximum mass concentration of hydride-forming or volatile elements causing no
interferences
Element
Sb Se Sn Te Hg
mg/l
1 1 0,1 1 0,1
If these concentrations are exceeded, it may be necessary to use the standard addition method (9.3).
Assuming that the arsenic content is high enough, an appropriate dilution of the water sample is
preferred.
4.3 Antimony
Elements such as arsenic, selenium, tellurium, mercury, and tin are also volatilized by this procedure
and may cause interferences. These elements do not cause interferences providing the concentrations
specified in Table 3 are not exceeded.
Table 3 — Maximum mass concentration of hydride-forming or volatile elements causing no
interferences
Element
As Se Sn Te Hg
mg/l
1 1 0,1 1 0,1
If these concentrations are exceeded, it may be necessary to use the standard addition method (9.3).
Assuming that the antimony content is high enough, an appropriate dilution of the water sample is
preferred.
5 Reagents
5.1 General requirements
It is important to use high purity reagents in all cases with minimum levels of arsenic or antimony.
Reagents may contain arsenic or antimony as an impurity. All reagents shall have arsenic or antimony
concentrations below that which would result in an arsenic or antimony blank value for the method
being above the lowest level of interest.
Use only reagents of recognized analytical grade, unless otherwise specified.
Reagents shall be prepared to manufacturer’s recommendations using the following series as an example.
5.2 Water, complying with grade 1 as defined in ISO 3696, for all sample preparation and dilutions.
5.3 Hydrochloric acid, ρ(HCl) = 1,16 g/ml.
5.4 Hydrochloric acid, c(HCl) = 1 mol/l.
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5.5 Sodium tetrahydroborate, NaBH .
4
Available as pellets. Keep the pellets dry and store in a cool, dark place.
5.6 Sodium hydroxide, NaOH.
5.7 Sodium tetrahydroborate solution, ρ(NaBH ) = 13 g/l.
4
Prepare appropriate quantities on day of use (13 g/l has proven suitable for the system illustrated in
Figure B.1).
Dissolve 0,4 g sodium hydroxide (5.6) and the appropriate quantity of sodium tetrahydroborate (5.5) in
800 ml of water and dilute to 1 000 ml.
Do not keep in a closed container because of potential pressure build-up due to hydrogen evolution.
Excess sodium borohydride solution should be slowly poured to drain with copious quantities of water.
Do not allow the solution to come into contact with acid during disposal.
NOTE The concentration of NaBH is dependent on the hybride generator manifold and flow-rate conditions.
4
See recommendations of the manufacturer.
Alternatively smaller volumes can be prepared on a pro rata basis.
5.8 Nitric acid, ρ(HNO ) = 1,40 g/ml.
3
NOTE Nitric acid is available both as ρ(HNO ) = 1,40 g/ml [w(HNO ) = 650 g/kg] and ρ(HNO ) = 1,42 g/ml
3 3 3
[w(HNO ) = 690 g/kg].
3
To prepare a nitric acid cleaning mixture, dilute nitric acid (1,40 g/ml) with an equal volume of water
(5.2) by carefully adding the acid to the water.
5.9 Potassium iodide–ascorbic acid solution.
Dissolve (250 ± 0,1) g of potassium iodide (KI) and (50 ± 0,1) g of ascorbic acid (C H O ) in approximately
6 8 6
400 ml water and dilute to 500 ml.
Prepare freshly on day of use. See Note to (5.7).
5.10 Reagent blank.
For each 1 000 ml, prepare a solution containing (300 ± 3) ml of hydrochloric acid (5.3) and (20 ± 0,5) ml
of potassium iodide–ascorbic acid solution (5.9). Dilute to volume with water (5.2).
IMPORTANT — On the continuous flow system, the reagent blank solution is run as background.
Since the blank solution can contain trace level detectable amounts of arsenic or antimony,
ensure that the same reagents are used for both sample and standard preparation as well as for
the preparation of the reagent blank.
The analyte signal is superimposed on the top of this signal once the sample is introduced into the
measurement cycle. Arsenic and antimony concentrations in the reagent blank solution should be less
than the lower levels of interest.
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5.11 Standard solutions (arsenic and antimony).
5.11.1 Arsenic solutions (standard, stock and calibration).
5.11.1.1 Arsenic stock solution A, ρ[As(III)] = 1 000 mg/l.
Use a quantitative stock solution with an arsenic(III) content of (1 000 ± 2) mg/l.
This solution is considered to be stable for at least one year.
NOTE If other stock solutions are available, they can be used providing the uncertainty of the measurement
is not compromised.
Alternatively, use a stock solution prepared from high purity grade chemicals:
Place (1,734 ± 0,002) g of sodium metaarsenite NaAsO in a 1 000 ml volumetric flask.
2
Add (50 ± 0,5) ml of hydrochloric acid (5.3) and dissolve the sodium metaarsenite completely by stirring.
Dilute to 1 l with water (5.2).
5.11.1.2 Arsenic standard solution B, ρ[As(III)] = 10 mg/l.
Pipette (1 ± 0,01) ml of arsenic stock solution A (5.11.1.1) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one month.
5.11.1.3 Arsenic standard solution C, ρ[As(III)] = 100 µg/l.
Pipette (1 ± 0,01) ml of arsenic standard solution B (5.11.1.2) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one week.
5.11.1.4 Arsenic stock solution D, ρ[As(V)] = 1 000 mg/l.
Dissolve (1,000 ± 0,002) g of pure arsenic powder in (10 ± 0,1) ml of concentrated nitric acid (5.8).
Heat the solution to boiling and evaporate off the excess nitric acid.
Perform this procedure carefully under a chemical hood.
Cool and then take up the hydrated arsenic(V) oxide in (50 ± 0,5) ml of cold hydrochloric acid (5.3).
Transfer the solution quantitatively to a 1 000 ml volumetric flask and fill up to the mark with water
(5.2).
This standard shall be used to prepare a suitable arsenic(V) standard to check quantitative recovery of
arsenic(V). Should the presence of arsenic(V) in the samples be suspected, use this standard to check
recovery of this analyte.
The solution is stable for at least six months.
NOTE If other stock solutions are available, they can be used providing the uncertainty of the measurement
is not compromised.
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5.11.1.5 Arsenic calibration solutions.
Use a minimum of five independent calibration solutions. Carry out the calibration as specified in
ISO 8466-1.
Prepare a minimum of five arsenic calibration solutions from the arsenic standard solution C (5.11.1.3)
covering the working range of expected arsenic concentrations.
For the operating range from 1 µg/l to 5 µg/l, for example, proceed e.g. as follows:
Pipette into a series of five 100 ml volumetric flasks (1 ± 0,01) ml, (2 ± 0,02) ml, (3 ± 0,03) ml, (4 ±
0,04) ml and (5 ± 0,05) ml, respectively, of arsenic standard solution C (5.11.1.3).
Add 30 ml of hydrochloric acid (5.3) and 2 ml of potassium iodide–ascorbic acid solution (5.9).
Dilute to 100 ml with water (5.2) and mix thoroughly.
Allow to stand for at least 2 h before using to ensure quantitative reduction of arsenic(V) to arsenic(III).
These calibration solutions contain 1 µg/l, 2 µg/l, 3 µg/l, 4 µg/l and 5 µg/l arsenic respectively.
They shall be prepared on the day of use.
The use of piston pipettes is permitted and enables the preparation of lower volumes of calibration
solutions. The application of dilutors is also allowed.
Once an established calibration pattern has been confirmed, the number of standards used routinely
may be reduced. Any such change shall not alter the result obtained from tests or the ranking with other
samples.
5.11.2 Antimony solutions (standard, stock and calibration).
5.11.2.1 Antimony stock solution A, ρ[Sb(III)] = 1 000 mg/l.
Use a quantitative stock solution with an antimony(III) content of (1 000 ± 2) mg/l.
This solution is considered to be stable for at least one year.
Alternatively, use a stock solution prepared from high purity grade chemicals:
Place (2,743 ± 0,002) g of potassium antimony(III) oxide tartrate hemihydrate, K(SbO)C H O ∙0,5H O
4 4 6 2
in a 1 000 ml volumetric flask.
Add (50 ± 0,5) ml of hydrochloric acid (5.3) and dissolve the potassium antimony(III) oxide tartrate
hemihydrate by stirring.
Dilute to 1 l with water (5.2).
5.11.2.2 Antimony standard solution B, ρ[Sb(III)] = 10 mg/l.
Pipette (1 ± 0,01) ml of antimony stock solution A (5.11.2.1) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,01) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one week.
NOTE If a suitable commercial standard is available, it can be used if performance validated.
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5.11.2.3 Antimony standard solution C, ρ[Sb(III)] = 100 µg/l.
Pipette (1 ± 0,01) ml of antimony standard solution B (5.11.2.2) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution shall be prepared weekly.
5.11.2.4 Antimony stock solution D, ρ[Sb(V)] = 1 000 mg/l.
Dissolve (1,000 ± 0,002) g of pure antimony powder in (10 ± 0,1) ml of concentrated nitric acid (5.8).
Heat the solution to boiling and evaporate off the excess nitric acid.
Perform this procedure carefully under a chemical hood.
Cool and then take up the hydrated antimony(V) oxide in (50 ± 0,5) ml of cold hydrochloric acid (5.3).
Transfer the solution quantitatively to a 1 000 ml volumetric flask and fill up to the mark with water
(5.2).
This standard should be used to prepare a suitable antimony(V) standard to check quantitative recovery
of antimony(V)
...
NORME ISO
INTERNATIONALE 17378-2
Première édition
2014-02-01
Qualité de l’eau — Dosage de l’arsenic
et de l’antimoine —
Partie 2:
Méthode par spectrométrie
d’absorption atomique à génération
d’hydrures (HG-AAS)
Water quality — Determination of arsenic and antimony —
Part 2: Method using hydride generation atomic absorption
spectrometry (HG-AAS)
Numéro de référence
ISO 17378-2:2014(F)
©
ISO 2014
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ISO 17378-2:2014(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2014
Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni utilisée
sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie, l’affichage sur
l’internet ou sur un Intranet, sans autorisation écrite préalable. Les demandes d’autorisation peuvent être adressées à l’ISO à
l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
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Publié en Suisse
ii © ISO 2014 – Tous droits réservés
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ISO 17378-2:2014(F)
Sommaire Page
Avant-propos .iv
Introduction .v
1 Domaine d’application . 1
2 Références normatives . 1
3 Principe . 2
3.1 Arsenic . 2
3.2 Antimoine . 2
4 Interférences . 2
4.1 Généralités . 2
4.2 Arsenic . 3
4.3 Antimoine . 3
5 Réactifs . 4
6 Appareillage . 8
7 Échantillonnage et préparation des échantillons . 9
7.1 Technique d’échantillonnage . 9
7.2 Réduction préalable .10
8 Réglage des instruments .10
9 Mode opératoire.11
9.1 Exigences générales .11
9.2 Analyse utilisant la méthode d’étalonnage normalisé .11
9.3 Analyse utilisant la technique de l’ajout dosé pour l’étalonnage .12
10 Étalonnage et analyse des données .13
10.1 Exigences générales .13
10.2 Calcul utilisant la courbe d’étalonnage .13
10.3 Calcul utilisant la technique de l’ajout dosé pour l’étalonnage .13
11 Expression des résultats.14
12 Rapport d’essai
.14
Annexe A (informative) Informations supplémentaires .15
Annexe B (informative) Diagramme de flux schématique et réponse du signal .16
Annexe C (informative) Exemple de technique d’enrichissement .18
Annexe D (informative) Données de performance .20
Bibliographie .23
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ISO 17378-2:2014(F)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.
L’ISO collabore étroitement avec la Commission électrotechnique internationale (CEI) en ce qui concerne
la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/CEI, Partie 1. Il convient, en particulier de prendre note des différents
critères d’approbation requis pour les différents types de documents ISO. Le présent document a été
rédigé conformément aux règles de rédaction données dans les Directives ISO/CEI, Partie 2 (voir www.
iso.org/directives).
L’attention est appelée sur le fait que certains des éléments du présent document peuvent faire l’objet de
droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant les
références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de l’élaboration
du document sont indiqués dans l’Introduction et/ou sur la liste ISO des déclarations de brevets reçues
(voir www.iso.org/brevets).
Les éventuelles appellations commerciales utilisées dans le présent document sont données pour
information à l’intention des utilisateurs et ne constituent pas une approbation ou une recommandation.
Pour une explication de la signification des termes et expressions spécifiques de l’ISO liés à l’évaluation
de la conformité, aussi bien que pour des informations au sujet de l’adhésion de l’ISO aux principes de
l’OMC concernant les obstacles techniques au commerce (OTC) voir le lien suivant: Avant-propos —
Informations supplémentaires.
Le comité chargé de l’élaboration du présent document est l’ISO/TC 147, Qualité de l’eau, sous-comité
SC 2, Méthodes physiques, chimiques et biochimiques.
Cette première édition de l’ISO 17378-2 annule et remplace l’ISO 11969:1996, qui a fait l’objet d’une
révision technique.
L’ISO 17378 comprend les parties suivantes, présentées sous le titre général Qualité de l’eau — Dosage
de l’arsenic et de l’antimoine:
— Partie 1: Méthode par spectrométrie de fluorescence atomique à génération d’hydrures (HG-AFS)
— Partie 2: Méthode par spectrométrie d’absorption atomique à génération d’hydrures (HG-AAS)
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Introduction
Il convient que la présente partie de l’ISO 17378 soit utilisée par des analystes ayant l’expérience du
traitement d’éléments trace présents à de très faibles concentrations.
Les concentrations d’arsenic dans les eaux naturelles sont extrêmement variables, de moins de 10 μg/l
jusqu’à plusieurs milligrammes par litre dans certaines parties de l’Asie, de l’Amérique du Sud et des
États-Unis, et en particulier dans le delta du Gange, où l’intoxication à l’arsenic provenant des puits
tubulaires contaminés est un problème grave. Les concentrations d’antimoine dans les eaux naturelles
sont généralement largement inférieures à 10 µg/l. L’arsenic ou l’antimoine sont naturellement présents
dans les composés organiques et inorganiques et peuvent avoir les états de valence –III, 0, III et V.
La décomposition totale de tous les composés de l’arsenic ou de l’antimoine nécessite un mode opératoire
de digestion. La digestion ne peut être omise que si l’on est certain que l’arsenic ou l’antimoine présent
dans l’échantillon peut former un hydrure covalent sans nécessiter d’étape de pré-oxydation.
Il convient que l’utilisateur ait à l’esprit que des problèmes particuliers sont susceptibles de nécessiter la
spécification de conditions secondaires supplémentaires.
La méthode pour le dosage de l’arsenic ou de l’antimoine est identique en tous points, à l’exception de
la préparation des solutions étalons à soumettre à essai. Pour éviter toute répétition ou duplication,
le texte fait à la fois référence à l’arsenic et à l’antimoine lorsqu’il est applicable dans les deux cas. Le
paragraphe qui décrit la préparation des solutions étalons, est divisé en 5.11.1 qui traite des solutions
d’arsenic et en 5.11.2 qui traite des solutions d’antimoine.
© ISO 2014 – Tous droits réservés v
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NORME INTERNATIONALE ISO 17378-2:2014(F)
Qualité de l’eau — Dosage de l’arsenic et de l’antimoine —
Partie 2:
Méthode par spectrométrie d’absorption atomique à
génération d’hydrures (HG-AAS)
AVERTISSEMENT — Il convient que l’utilisateur du présent document connaisse bien les pratiques
courantes de laboratoire. Le présent document n’a pas pour but de traiter tous les problèmes
de sécurité qui sont, le cas échéant, liés à son utilisation. Il incombe à l’utilisateur d’établir des
pratiques appropriées en matière d’hygiène et de sécurité, et de s’assurer de la conformité à la
réglementation nationale en vigueur.
IMPORTANT — Il est absolument essentiel que les essais réalisés conformément au présent
document soient exécutés par un personnel ayant reçu une formation adéquate.
1 Domaine d’application
La présente partie de l’ISO 17378 spécifie une méthode pour le dosage de l’arsenic et de l’antimoine.
Cette méthode s’applique à l’eau potable, aux eaux de surface, aux eaux souterraines et à l’eau de pluie.
La plage d’application linéaire de la présente partie de l’ISO 17378 s’étend de 0,5 µg/l à 20 µg/l. Les
échantillons contenant de l’arsenic ou de l’antimoine dans des concentrations plus élevées que la plage
d’application peuvent être analysés après une dilution appropriée.
L’eau de mer n’entre généralement pas dans le domaine d’application de la présente partie de l’ISO 17378.
Les échantillons d’eau de mer peuvent être analysés à l’aide d’une technique de l’ajout dosé dans la mesure
où celle-ci a été validée pour les échantillons soumis à essai. Il est peu probable que cette méthode
détecte des composés organoarséniés et organoantimoniés.
La sensibilité de cette méthode dépend des conditions opératoires choisies.
2 Références normatives
Les documents ci-après, dans leur intégralité ou non, sont des références normatives indispensables à
l’application du présent document. Pour les références datées, seule l’édition citée s’applique. Pour les
références non datées, la dernière édition du document de référence s’applique (y compris les éventuels
amendements).
ISO 3696, Eau pour laboratoire à usage analytique — Spécification et méthodes d’essai
ISO 5667-1, Qualité de l’eau — Échantillonnage — Partie 1: Lignes directrices pour la conception des
programmes et des techniques d’échantillonnage
ISO 5667-3, Qualité de l’eau — Échantillonnage — Partie 3: Conservation et manipulation des échantillons
d’eau
ISO 5667-5, Qualité de l’eau — Échantillonnage — Partie 5: Lignes directrices pour l’échantillonnage de
l’eau potable des usines de traitement et du réseau de distribution
ISO 5667-6, Qualité de l’eau — Échantillonnage — Partie 6: Lignes directrices pour l’échantillonnage des
rivières et des cours d’eau
ISO 5667-8, Qualité de l’eau — Échantillonnage — Partie 8: Guide général pour l’échantillonnage des dépôts
humides
© ISO 2014 – Tous droits réservés 1
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ISO 17378-2:2014(F)
ISO 5667-11, Qualité de l’eau — Échantillonnage — Partie 11: Lignes directrices pour l’échantillonnage des
eaux souterraines
ISO 8466-1, Qualité de l’eau — Étalonnage et évaluation des méthodes d’analyse et estimation des caractères
de performance — Partie 1: Évaluation statistique de la fonction linéaire d’étalonnage
ISO 8466-2, Qualité de l’eau — Étalonnage et évaluation des méthodes d’analyse et estimation des caractères
de performance — Partie 2: Stratégie d’étalonnage pour fonctions d’étalonnage non linéaires du second
degré
ISO 15587-1, Qualité de l’eau — Digestion pour la détermination de certains éléments dans l’eau — Partie 1:
Digestion à l’eau régale
3 Principe
NOTE D’autres techniques de mesure peuvent être applicables à condition que le laboratoire utilisateur puisse
démontrer de manière appropriée que les critères de performance sont remplis ou dépassés. (Voir Annexe C).
3.1 Arsenic
Une partie aliquote de l’échantillon est acidifiée avec de l’acide chlorhydrique (5.3). Le réactif iodure
de potassium-acide ascorbique (5.9) est ajouté pour garantir la réduction quantifiée d’arsenic(V) en
arsenic(III). Les solutions d’échantillon sont traitées avec du tétrahydroborate de sodium (5.5) afin de
générer le trihydrure d’arsenic gazeux covalent (arsine, AsH ). L’hydrure et l’hydrogène en excès sont
3
entraînés hors du récipient où ils ont été générés (mode discontinu) ou hors du séparateur gaz/liquide
(mode en flux continu), jusque dans une cuve en silice chauffée. Après atomisation, l’absorbance de
l’arsenic est déterminée à une longueur d’onde λ = 193,7 nm. Ce mode opératoire est automatisé au
moyen d’un passeur d’échantillons et d’un logiciel de contrôle.
3.2 Antimoine
Une partie aliquote de l’échantillon est digérée avec de l’acide chlorhydrique (5.3). Le réactif iodure
de potassium-acide ascorbique (5.9) est ajouté pour garantir la réduction quantifiée de l’antimoine(V)
en antimoine(III). Les solutions d’échantillon sont traitées avec du tétrahydroborate de sodium (5.5)
afin de générer le trihydrure d’antimoine gazeux covalent (stibane, SbH ). L’hydrure et l’hydrogène en
3
excès sont entraînés hors du récipient où ils ont été générés (mode discontinu) ou hors du séparateur
gaz/liquide (mode en flux continu). Après atomisation, l’absorbance de l’antimoine est déterminée à une
longueur d’onde λ = 217,6 nm. Ce mode opératoire est automatisé au moyen d’un passeur d’échantillons
et d’un logiciel de contrôle.
4 Interférences
4.1 Généralités
La technique de génération d’hydrures est sujette aux interférences dues aux métaux de transition et aux
métaux facilement réductibles. Pour la majorité des échantillons d’eaux naturelles, ce type d’interférence
ne doit pas être significatif. Il convient que l’utilisateur réalise des essais de récupération sur des eaux
type et détermine également la concentration maximale d’éléments potentiellement interférents, en
utilisant des méthodes appropriées. Si de telles interférences sont constatées, il convient d’évaluer leur
niveau en procédant à des ajouts dosés.
Les métaux facilement réduits par du tétrahydroborate de sodium peuvent également causer des
interférences. Il s’agit entre autres des métaux suivants: chrome, fer, cuivre, nickel et plomb. Si la
concentration de ces éléments, spécifiée dans le Tableau 1, est dépassée, une baisse significative de
l’absorption peut se produire.
2 © ISO 2014 – Tous droits réservés
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ISO 17378-2:2014(F)
Tableau 1 — Concentration en masse maximale dans la solution d’essai de métaux lourds
interférents (valable pour des systèmes d’analyse en flux)
Élément interférent
Cr Fe Cu Ni Pb
mg/l
500 500 500 250 100
Les conditions de réaction dans la présente partie de l’ISO 17378 ont été choisies pour minimiser ces
interférences.
Des informations complémentaires sur ces interférences et sur la technique sont données en
Références [1] et [2].
NOTE Si des systèmes d’analyse par lots sont utilisés, les concentrations en masse qui sont sensiblement
inférieures à celles spécifiées dans les Tableaux 1, 2 et 3 peuvent causer des interférences.
4.2 Arsenic
Les éléments comme l’antimoine, le sélénium, le tellure, le mercure et l’étain sont également volatilisés par
ce mode opératoire et peuvent causer des interférences. Ces éléments ne provoquent pas d’interférence
si les concentrations spécifiées dans le Tableau 2 ne sont pas dépassées.
Tableau 2 — Concentration en masse maximale d’éléments formant des hydrures ou d’éléments
volatils et ne causant pas d’interférence
Élément
Sb Se Sn Te Hg
mg/l
1 1 0,1 1 0,1
Si ces concentrations sont dépassées, il peut être nécessaire d’utiliser la technique de l’ajout dosé (9.3).
Si l’on suppose que la teneur en arsenic est suffisamment élevée, il est recommandé de procéder à une
dilution appropriée de l’échantillon d’eau.
4.3 Antimoine
Les éléments comme l’arsenic, le sélénium, le tellure, le mercure et l’étain sont également volatilisés par
ce mode opératoire et peuvent causer des interférences. Ces éléments ne provoquent pas d’interférence
si les concentrations spécifiées dans le Tableau 3 ne sont pas dépassées.
Tableau 3 — Concentration en masse maximale d’éléments formant des hydrures ou d’éléments
volatils et ne causant pas d’interférence
Élément
As Se Sn Te Hg
mg/l
1 1 0,1 1 0,1
Si ces concentrations sont dépassées, il peut être nécessaire d’utiliser la technique de l’ajout dosé (9.3).
Si l’on suppose que la teneur en antimoine est suffisamment élevée, il est recommandé de procéder à une
dilution appropriée de l’échantillon d’eau.
© ISO 2014 – Tous droits réservés 3
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ISO 17378-2:2014(F)
5 Réactifs
5.1 Exigences générales.
Il est important d’utiliser des réactifs de grande pureté dans tous les cas, avec un niveau minimal
d’arsenic ou d’antimoine.
Des réactifs peuvent contenir de l’arsenic ou de l’antimoine comme impureté. Tous les réactifs doivent
présenter des concentrations d’arsenic ou d’antimoine inférieures à celles qui entraîneraient une valeur
à blanc d’arsenic ou d’antimoine pour la méthode étant au-dessus du niveau d’intérêt le plus bas.
Sauf spécification contraire, utiliser uniquement des réactifs de qualité analytique reconnue.
Les réactifs doivent être préparés selon les recommandations du fabricant, en utilisant la série suivante
comme exemple.
5.2 Eau, de qualité 1 tel que défini dans l’ISO 3696, pour la préparation et les dilutions de tous les
échantillons.
5.3 Acide chlorhydrique, ρ(HCl) = 1,16 g/ml.
5.4 Acide chlorhydrique, c(HCl) = 1 mol/l.
5.5 Tétrahydroborate de sodium, NaBH .
4
Disponible sous forme de pastilles.
Conserver les pastilles au sec, à l’abri de la lumière et de la chaleur.
5.6 Hydroxyde de sodium, NaOH.
5.7 Solution de tétrahydroborate de sodium, ρ(NaBH ) = 13 g/l.
4
Préparer des quantités appropriées le jour de l’utilisation (13 g se sont révélés adaptés pour le système
illustré à la Figure B.1).
Dissoudre 0,4 g d’hydroxyde de sodium (5.6) ainsi que la quantité appropriée de tétrahydroborate de
sodium (5.5) dans 800 ml d’eau et diluer pour obtenir 1 000 ml de solution.
Ne pas conserver la solution dans un récipient fermé en raison de l’augmentation potentielle de pression
due à un dégagement d’hydrogène.
Il convient de vider lentement à l’évier la solution de tétrahydroborate de sodium en excès, avec de
grandes quantités d’eau. Éviter tout contact avec les acides lors de l’élimination de la solution.
NOTE La concentration de NaBH dépend des conditions de débit et du manifold du générateur d’hydrures.
4
Voir les recommandations du fabricant.
Il est également possible de préparer de plus petits volumes au prorata.
5.8 Acide nitrique, ρ(HNO ) = 1,40 g/ml.
3
NOTE L’acide nitrique est disponible à la fois sous la forme ρ(HNO ) = 1,40 g/ml [w(HNO ) = 650 g/kg] et
3 3
ρ(HNO ) = 1,42 g/ml [w(HNO ) = 690 g/kg].
3 3
Pour préparer un mélange d’acide nitrique pour nettoyage, diluer l’acide nitrique (1,40 g/ml) avec un
volume d’eau équivalent (5.2) en ajoutant avec précaution l’acide à l’eau.
4 © ISO 2014 – Tous droits réservés
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ISO 17378-2:2014(F)
5.9 Solution d’iodure de potassium et d’acide ascorbique.
Dissoudre (250 ± 0,1) g d’iodure de potassium (KI) et (50 ± 0,1) g d’acide ascorbique (C H O ) dans
6 8 6
environ 400 ml, puis diluer pour obtenir 500 ml de solution.
Préparer fraîchement le jour de l’utilisation. Voir Note en 5.7.
5.10 Solution de blanc réactif.
Pour 1 000 ml, préparer une solution contenant (300 ± 3) ml d’acide chlorhydrique (5.3) et (20 ± 0,5) ml
de solution d’iodure de potassium et d’acide ascorbique (5.9). Diluer au volume avec de l’eau (5.2).
IMPORTANT — Sur le système en flux continu, la solution de blanc réactif sert de fond. Comme la
solution à blanc peut contenir des quantités d’arsenic ou d’antimoine détectables sous forme de
traces, s’assurer que les mêmes réactifs sont utilisés pour la préparation des échantillons et des
étalons ainsi que pour la préparation de la solution de blanc réactif.
Le signal de l’analyte se superpose à ce signal une fois que l’échantillon est introduit dans le cycle de
mesurage. Il convient que les concentrations d’arsenic et d’antimoine de la solution de blanc réactif
soient inférieures au niveau d’intérêt le plus bas.
5.11 Solutions étalons (arsenic et antimoine).
5.11.1 Solutions d’arsenic (solutions étalons, mères et d’étalonnage).
5.11.1.1 Solution mère d’arsenic A, ρ[As(III)] = 1 000 mg/l.
Utiliser une solution mère quantitative ayant une teneur traçable en arsenic(III) de (1 000 ± 2) mg/l.
Cette solution est considérée comme stable pendant au moins un an.
NOTE Si d’autres solutions mères sont disponibles, elles peuvent être utilisées dans la mesure où l’incertitude
du mesurage n’est pas compromise.
Il est également possible d’utiliser une solution mère préparée à partir de produits chimiques d’une
grande pureté.
Placer (1,734 ± 0,002) g de métaarsénite de sodium NaAsO dans une fiole jaugée de 1 100 ml.
2
Ajouter (50 ± 0,5) ml d’acide chlorhydrique (5.3) et agiter pour dissoudre complètement le métaarsénite
de sodium.
Diluer avec de l’eau (5.2) pour obtenir 1 l de solution.
5.11.1.2 Solution étalon d’arsenic B, ρ[As(III)] = 10 mg/l.
Mesurer avec une pipette (1 ± 0,01) ml de solution mère d’arsenic A (5.11.1.1) dans une fiole jaugée de
100 ml, ajouter (30 ± 0,5) ml d’acide chlorhydrique (5.3) et (2 ± 0,1) ml de solution d’iodure de potassium
et d’acide ascorbique (5.9), puis remplir avec de l’eau (5.2) jusqu’au trait.
Cette solution est stable pendant un mois.
5.11.1.3 Solution étalon d’arsenic C, ρ[As(III)] = 100 µg/l.
Mesurer avec une pipette (1 ± 0,01) ml de solution étalon d’arsenic B (5.11.1.2) dans une fiole jaugée de
100 ml, ajouter (30 ± 0,5) ml d’acide chlorhydrique (5.3) et (2 ± 0,1) ml de solution d’iodure de potassium
et d’acide ascorbique (5.9), puis remplir avec de l’eau (5.2) jusqu’au trait.
Cette solution est stable pendant une semaine.
© ISO 2014 – Tous droits réservés 5
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ISO 17378-2:2014(F)
5.11.1.4 Solution mère d’arsenic D, ρ[As(V)] = 1 000 mg/l.
Dissoudre (1,000 ± 0,002) g de poudre d’arsenic pur dans (10 ± 0,1) ml d’acide nitrique concentré (5.8).
Chauffer la solution jusqu’à ébullition et faire évaporer l’acide nitrique en excès.
Exécuter ce mode opératoire avec précaution sous la hotte chimique.
Refroidir puis récupérer l’oxyde d’arsenic(V) hydraté avec (50 ± 0,5) ml d’acide chlorhydrique froid (5.3).
Transvaser la solution quantitativement dans une fiole jaugée de 1 000 ml et remplir d’eau (5.2) jusqu’au
trait.
Cet étalon doit être utilisé pour préparer un étalon d’arsenic(V) approprié afin de vérifier le taux de
récupération de l’arsenic(V). En cas de suspicion de présence d’arsenic(V) dans les échantillons, utiliser
cet étalon pour vérifier la récupération de cet analyte.
La solution est stable pendant au moins six mois.
NOTE Si d’autres solutions mères sont disponibles, elles peuvent être utilisées dans la mesure où l’incertitude
du mesurage n’est pas compromise.
5.11.1.5 Solutions d’étalonnage d’arsenic.
Utiliser au minimum cinq solutions d’étalonnage indépendantes. Réaliser l’étalonnage comme spécifié
dans l’ISO 8466-1.
Préparer au minimum cinq solutions d’étalonnage d’arsenic à partir de la solution étalon d’arsenic C
(5.11.1.3) couvrant le domaine de travail des concentrations d’arsenic attendues.
Pour la plage opératoire de 1 µg/l à 5 µg/l, par exemple, procéder comme suit.
Mesurer avec une pipette respectivement (1 ± 0,01) ml, (2 ± 0,02) ml, (3 ± 0,03) ml, (4 ± 0,04) ml et
(5 ± 0,05) ml de solution étalon d’arsenic C (5.11.1.3) dans cinq fioles jaugées de 100 ml.
Ajouter 30 ml d’acide chlorhydrique (5.3) et 2 ml de solution d’iodure de potassium et d’acide ascorbique
(5.9).
Diluer avec de l’eau (5.2) pour obtenir 100 ml de solution et mélanger vigoureusement.
Laisser reposer la solution pendant au moins 2 h avant de l’utiliser afin de s’assurer de la réduction
quantitative de l’arsenic(V) en arsenic(III).
Ces solutions d’étalonnage contiennent respectivement 1 µg/l, 2 µg/l, 3 µg/l, 4 µg/l et 5 µg/l d’arsenic.
Elles doivent être préparées le jour de l’utilisation.
L’utilisation de pipettes à piston est autorisée et permet de préparer des volumes plus faibles de solutions
d’étalonnage. Il est également permis d’utiliser des diluteurs.
Une fois qu’un profil d’étalonnage bien établi a été confirmé, le nombre d’étalons couramment utilisés
peut être réduit. Toute modification de ce genre ne doit pas affecter le résultat obtenu suite aux essais
ou le classement de l’échantillon par rapport à d’autres.
5.11.2 Solutions d’antimoine (solutions étalons, mères et d’étalonnage).
5.11.2.1 Solution mère d’antimoine A, ρ[Sb(III)] = 1 000 mg/l.
Utiliser une solution mère quantitative ayant une teneur traçable en antimoine(III) de (1 000 ± 2) mg/l.
Cette solution est considérée comme stable pendant au moins un an.
6 © ISO 2014 – Tous droits réservés
---------------------- Page: 11 ----------------------
ISO 17378-2:2014(F)
Il est également possible d’utiliser une solution mère préparée à partir de produits chimiques d’une
grande pureté.
Placer (2,743 ± 0,002) g d’hémihydrate de tartrate d’antimoine(III) et de potassium, K(SbO)
C H O , 0,5H O, dans une fiole jaugée de 1 000 ml.
4 4 6 2
Ajouter (50 ± 0,5) ml d’acide chlorhydrique (5.3) et agiter pour diss
...
SLOVENSKI STANDARD
oSIST ISO 17378-2:2019
01-maj-2019
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VSHNWURPHWULMVNDPHWRGDVKLGULGQRWHKQLNR +*$$6
Water quality - Determination of arsenic and antimony - Part 2: Method using hydride
generation atomic absorption spectrometry (HG-AAS)
Qualité de l'eau - Dosage de l'arsenic et de l'antimoine - Partie 2: Méthode par
spectrométrie d'absorption atomique à génération d'hydrures (HG-AAS)
Ta slovenski standard je istoveten z: ISO 17378-2:2014
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
oSIST ISO 17378-2:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST ISO 17378-2:2019
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oSIST ISO 17378-2:2019
INTERNATIONAL ISO
STANDARD 17378-2
First edition
2014-02-01
Water quality — Determination of
arsenic and antimony —
Part 2:
Method using hydride generation
atomic absorption spectrometry (HG-
AAS)
Qualité de l’eau — Dosage de l’arsenic et de l’antimoine —
Partie 2: Méthode par spectrométrie d’absorption atomique à
génération d’hydrures (HG-AAS)
Reference number
ISO 17378-2:2014(E)
©
ISO 2014
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oSIST ISO 17378-2:2019
ISO 17378-2:2014(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved
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oSIST ISO 17378-2:2019
ISO 17378-2:2014(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Principle . 2
3.1 Arsenic . 2
3.2 Antimony . 2
4 Interferences . 2
4.1 General . 2
4.2 Arsenic . 3
4.3 Antimony . 3
5 Reagents . 3
5.1 General requirements . 3
6 Apparatus . 8
7 Sampling and sample preparation . 9
7.1 Sampling technique . 9
7.2 Pre-reduction . 9
8 Instrumental set up .10
9 Procedure.10
9.1 General requirements .10
9.2 Analysis using the method of standard calibration .11
9.3 Analysis using the standard addition method of calibration .11
10 Calibration and data analysis .12
10.1 General requirements .12
10.2 Calculation using the calibration curve .12
10.3 Calculation using the standard addition method .13
11 Expression of results .13
12 Test report .13
Annex A (informative) Additional information .14
Annex B (informative) Schematic flow diagram and signal response .15
Annex C (informative) Example of enrichment technique .17
Annex D (informative) Performance data .19
Bibliography .22
© ISO 2014 – All rights reserved iii
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oSIST ISO 17378-2:2019
ISO 17378-2:2014(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 (see 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 (see 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.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
This first edition of ISO 17378-2 cancels and replaces ISO 11969:1996, which has been technically
revised.
ISO 17378 consists of the following parts, under the general title Water quality — Determination of
arsenic and antimony:
— Part 1: Method using hydride generation atomic fluorescence spectrometry (HG–AFS)
— Part 2: Method using hydride generation atomic absorption spectrometry (HG–AAS)
iv © ISO 2014 – All rights reserved
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oSIST ISO 17378-2:2019
ISO 17378-2:2014(E)
Introduction
This part of ISO 17378 should be used by analysts experienced in the handling of trace elements at very
low concentrations.
Arsenic concentrations in natural waters are highly variable, from <10 μg/l to as high as several
milligrams per litre in some parts of Asia, South America and the USA, notable in the Ganges delta
where arsenic poisoning from contaminated tube wells is a serious problem. Antimony concentrations
in natural waters are generally well below 10 μg/l. Arsenic and antimony occur naturally in organic and
inorganic compounds and may have oxidation states −III, 0, III and V.
In order to fully decompose all of the arsenic or antimony compounds, a digestion procedure is necessary.
Digestion can only be omitted if it is certain that the arsenic or antimony in the sample can form a
covalent hydride without the necessity of a pre-oxidation step.
The user should be aware that particular problems could require the specification of additional marginal
conditions.
The method for determining arsenic or antimony is identical in all aspects except for the preparation
of standard solutions to be tested. To avoid repetition or duplication the text refers to both arsenic and
antimony where the text is equally applicable to both instances. The subclause dealing with preparation
of standard solutions is divided into 5.11.1, which deals with solutions of arsenic, and 5.11.2, which deals
with solutions of antimony.
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oSIST ISO 17378-2:2019
INTERNATIONAL STANDARD ISO 17378-2:2014(E)
Water quality — Determination of arsenic and antimony —
Part 2:
Method using hydride generation atomic absorption
spectrometry (HG-AAS)
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document 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 according to this document be
carried out by suitably trained and experienced staff.
1 Scope
This part of ISO 17378 specifies a method for the determination of arsenic and antimony. The method
is applicable to drinking water, surface water, ground water, and rain water. The approximate linear
application range of this part of ISO 17378 for both elements is from 0,5 µg/l to 20 µg/l. Samples
containing higher concentrations than the application range can be analysed following appropriate
dilution.
Generally sea water is outside the scope of this part of ISO 17378. Sea water samples can be analysed
using a standard additions approach providing that this is validated for the samples under test. The
method is unlikely to detect organo-arsenic and organo-antimony compounds.
The sensitivity of this method is dependent on the selected operating conditions.
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 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 5667-5, Water quality — Sampling — Part 5: Guidance on sampling of drinking water from treatment
works and piped distribution systems
ISO 5667-6, Water quality — Sampling — Part 6: Guidance on sampling of rivers and streams
ISO 5667-8, Water quality — Sampling — Part 8: Guidance on the sampling of wet deposition
ISO 5667-11, Water quality — Sampling — Part 11: Guidance on sampling of groundwaters
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
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ISO 15587-1, Water quality — Digestion for the determination of selected elements in water — Part 1: Aqua
regia digestion
3 Principle
NOTE Other measurement techniques can be applicable providing the performance criteria are adequately
demonstrated to be fulfilled or exceeded by the user laboratory. (See Annex C.)
3.1 Arsenic
An aliquot of sample is acidified with hydrochloric acid (5.3). Potassium iodide–ascorbic acid reagent
(5.9) is added to ensure quantified reduction of arsenic(V) to arsenic(III). The sample solutions are
treated with sodium tetrahydroborate (5.5) to generate the covalent gaseous arsenic trihydride (arsine,
AsH ). The hydride and excess hydrogen are swept out of the generation vessel in case of batch mode and
3
out of the gas/liquid separator in case of the continuous mode into a heated silica cell. After atomization,
the absorbance of arsenic is determined at a wavelength λ = 193,7 nm. The procedure is automated by
means of auto-sampler and control software.
3.2 Antimony
An aliquot of sample is digested with hydrochloric acid (5.3). Potassium iodide–ascorbic acid reagent
(5.9) is added to ensure quantified reduction of the antimony(V) to antimony(III). The sample solutions
are then treated with sodium tetrahydroborate (5.5) to generate the covalent gaseous antimony
trihydride (stibane, SbH ). The hydride and excess hydrogen are swept out of the generation vessel in
3
case of batch mode and out of the gas/liquid separator in case of continuous mode. After atomization,
the absorbance of antimony is determined at a wavelength λ = 217,6 nm. The procedure is automated by
means of auto-sampler and control software.
4 Interferences
4.1 General
The hydride generation technique is prone to interferences by transition and easily reducible metals.
For the majority of natural water samples, this type of interference shall not be significant. The user
should carry out recovery tests on typical waters and also determine the maximum concentrations of
potentially interfering elements, using appropriate methods. If such interferences are indicated, the
level of interferences should be assessed by performing spike recoveries.
Metals which are readily reduced by sodium tetrahydroborate may also cause interferences. In particular,
these include chromium, iron, copper, nickel, and lead. If the concentrations of these elements specified
in Table 1 are exceeded, a significant decrease of absorption may occur.
Table 1 — Maximum mass concentration in test solution of interfering heavy metals
(valid for flow systems)
Interfering element
Cr Fe Cu Ni Pb
mg/l
500 500 500 250 100
The reaction conditions in this part of ISO 17378 have been chosen to minimize these interferences.
[1][2]
Further information on these interferences and the technique are given in References.
NOTE If batch systems are used, mass concentrations which are appreciably lower than those specified in
Table 1, Table 2 and Table 3 can cause interferences.
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4.2 Arsenic
Elements such as antimony, selenium, tellurium, mercury, and tin are also volatilized by this procedure
and may cause interferences. These elements do not cause interferences providing the concentrations
specified in Table 2 are not exceeded.
Table 2 — Maximum mass concentration of hydride-forming or volatile elements causing no
interferences
Element
Sb Se Sn Te Hg
mg/l
1 1 0,1 1 0,1
If these concentrations are exceeded, it may be necessary to use the standard addition method (9.3).
Assuming that the arsenic content is high enough, an appropriate dilution of the water sample is
preferred.
4.3 Antimony
Elements such as arsenic, selenium, tellurium, mercury, and tin are also volatilized by this procedure
and may cause interferences. These elements do not cause interferences providing the concentrations
specified in Table 3 are not exceeded.
Table 3 — Maximum mass concentration of hydride-forming or volatile elements causing no
interferences
Element
As Se Sn Te Hg
mg/l
1 1 0,1 1 0,1
If these concentrations are exceeded, it may be necessary to use the standard addition method (9.3).
Assuming that the antimony content is high enough, an appropriate dilution of the water sample is
preferred.
5 Reagents
5.1 General requirements
It is important to use high purity reagents in all cases with minimum levels of arsenic or antimony.
Reagents may contain arsenic or antimony as an impurity. All reagents shall have arsenic or antimony
concentrations below that which would result in an arsenic or antimony blank value for the method
being above the lowest level of interest.
Use only reagents of recognized analytical grade, unless otherwise specified.
Reagents shall be prepared to manufacturer’s recommendations using the following series as an example.
5.2 Water, complying with grade 1 as defined in ISO 3696, for all sample preparation and dilutions.
5.3 Hydrochloric acid, ρ(HCl) = 1,16 g/ml.
5.4 Hydrochloric acid, c(HCl) = 1 mol/l.
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5.5 Sodium tetrahydroborate, NaBH .
4
Available as pellets. Keep the pellets dry and store in a cool, dark place.
5.6 Sodium hydroxide, NaOH.
5.7 Sodium tetrahydroborate solution, ρ(NaBH ) = 13 g/l.
4
Prepare appropriate quantities on day of use (13 g/l has proven suitable for the system illustrated in
Figure B.1).
Dissolve 0,4 g sodium hydroxide (5.6) and the appropriate quantity of sodium tetrahydroborate (5.5) in
800 ml of water and dilute to 1 000 ml.
Do not keep in a closed container because of potential pressure build-up due to hydrogen evolution.
Excess sodium borohydride solution should be slowly poured to drain with copious quantities of water.
Do not allow the solution to come into contact with acid during disposal.
NOTE The concentration of NaBH is dependent on the hybride generator manifold and flow-rate conditions.
4
See recommendations of the manufacturer.
Alternatively smaller volumes can be prepared on a pro rata basis.
5.8 Nitric acid, ρ(HNO ) = 1,40 g/ml.
3
NOTE Nitric acid is available both as ρ(HNO ) = 1,40 g/ml [w(HNO ) = 650 g/kg] and ρ(HNO ) = 1,42 g/ml
3 3 3
[w(HNO ) = 690 g/kg].
3
To prepare a nitric acid cleaning mixture, dilute nitric acid (1,40 g/ml) with an equal volume of water
(5.2) by carefully adding the acid to the water.
5.9 Potassium iodide–ascorbic acid solution.
Dissolve (250 ± 0,1) g of potassium iodide (KI) and (50 ± 0,1) g of ascorbic acid (C H O ) in approximately
6 8 6
400 ml water and dilute to 500 ml.
Prepare freshly on day of use. See Note to (5.7).
5.10 Reagent blank.
For each 1 000 ml, prepare a solution containing (300 ± 3) ml of hydrochloric acid (5.3) and (20 ± 0,5) ml
of potassium iodide–ascorbic acid solution (5.9). Dilute to volume with water (5.2).
IMPORTANT — On the continuous flow system, the reagent blank solution is run as background.
Since the blank solution can contain trace level detectable amounts of arsenic or antimony,
ensure that the same reagents are used for both sample and standard preparation as well as for
the preparation of the reagent blank.
The analyte signal is superimposed on the top of this signal once the sample is introduced into the
measurement cycle. Arsenic and antimony concentrations in the reagent blank solution should be less
than the lower levels of interest.
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5.11 Standard solutions (arsenic and antimony).
5.11.1 Arsenic solutions (standard, stock and calibration).
5.11.1.1 Arsenic stock solution A, ρ[As(III)] = 1 000 mg/l.
Use a quantitative stock solution with an arsenic(III) content of (1 000 ± 2) mg/l.
This solution is considered to be stable for at least one year.
NOTE If other stock solutions are available, they can be used providing the uncertainty of the measurement
is not compromised.
Alternatively, use a stock solution prepared from high purity grade chemicals:
Place (1,734 ± 0,002) g of sodium metaarsenite NaAsO in a 1 000 ml volumetric flask.
2
Add (50 ± 0,5) ml of hydrochloric acid (5.3) and dissolve the sodium metaarsenite completely by stirring.
Dilute to 1 l with water (5.2).
5.11.1.2 Arsenic standard solution B, ρ[As(III)] = 10 mg/l.
Pipette (1 ± 0,01) ml of arsenic stock solution A (5.11.1.1) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one month.
5.11.1.3 Arsenic standard solution C, ρ[As(III)] = 100 µg/l.
Pipette (1 ± 0,01) ml of arsenic standard solution B (5.11.1.2) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one week.
5.11.1.4 Arsenic stock solution D, ρ[As(V)] = 1 000 mg/l.
Dissolve (1,000 ± 0,002) g of pure arsenic powder in (10 ± 0,1) ml of concentrated nitric acid (5.8).
Heat the solution to boiling and evaporate off the excess nitric acid.
Perform this procedure carefully under a chemical hood.
Cool and then take up the hydrated arsenic(V) oxide in (50 ± 0,5) ml of cold hydrochloric acid (5.3).
Transfer the solution quantitatively to a 1 000 ml volumetric flask and fill up to the mark with water
(5.2).
This standard shall be used to prepare a suitable arsenic(V) standard to check quantitative recovery of
arsenic(V). Should the presence of arsenic(V) in the samples be suspected, use this standard to check
recovery of this analyte.
The solution is stable for at least six months.
NOTE If other stock solutions are available, they can be used providing the uncertainty of the measurement
is not compromised.
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5.11.1.5 Arsenic calibration solutions.
Use a minimum of five independent calibration solutions. Carry out the calibration as specified in
ISO 8466-1.
Prepare a minimum of five arsenic calibration solutions from the arsenic standard solution C (5.11.1.3)
covering the working range of expected arsenic concentrations.
For the operating range from 1 µg/l to 5 µg/l, for example, proceed e.g. as follows:
Pipette into a series of five 100 ml volumetric flasks (1 ± 0,01) ml, (2 ± 0,02) ml, (3 ± 0,03) ml, (4 ±
0,04) ml and (5 ± 0,05) ml, respectively, of arsenic standard solution C (5.11.1.3).
Add 30 ml of hydrochloric acid (5.3) and 2 ml of potassium iodide–ascorbic acid solution (5.9).
Dilute to 100 ml with water (5.2) and mix thoroughly.
Allow to stand for at least 2 h before using to ensure quantitative reduction of arsenic(V) to arsenic(III).
These calibration solutions contain 1 µg/l, 2 µg/l, 3 µg/l, 4 µg/l and 5 µg/l arsenic respectively.
They shall be prepared on the day of use.
The use of piston pipettes is permitted and enables the preparation of lower volumes of calibration
solutions. The application of dilutors is also allowed.
Once an established calibration pattern has been confirmed, the number of standards used routinely
may be reduced. Any such change shall not alter the result obtained from tests or the ranking with other
samples.
5.11.2 Antimony solutions (standard, stock and calibration).
5.11.2.1 Antimony stock solution A, ρ[Sb(III)] = 1 000 mg/l.
Use a quantitative stock solution with an antimony(III) content of (1 000 ± 2) mg/l.
This solution is considered to be stable for at least one year.
Alternatively, use a stock solution prepared from high purity grade chemicals:
Place (2,743 ± 0,002) g of potassium antimony(III) oxide tartrate hemihydrate, K(SbO)C H O ∙0,5H O
4 4 6 2
in a 1 000 ml volumetric flask.
Add (50 ± 0,5) ml of hydrochloric acid (5.3) and dissolve the potassium antimony(III) oxide tartrate
hemihydrate by stirring.
Dilute to 1 l with water (5.2).
5.11.2.2 Antimony standard solution B, ρ[Sb(III)] = 10 mg/l.
Pipette (1 ± 0,01) ml of antimony stock solution A (5.11.2.1) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,01) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution is stable for one week.
NOTE If a suitable commercial standard is available, it can be used if performance validated.
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5.11.2.3 Antimony standard solution C, ρ[Sb(III)] = 100 µg/l.
Pipette (1 ± 0,01) ml of antimony standard solution B (5.11.2.2) into a 100 ml volumetric flask, add (30 ±
0,5) ml of hydrochloric acid (5.3) and (2 ± 0,1) ml of potassium iodide–ascorbic acid solution (5.9) and
fill up to the mark with water (5.2).
This solution shall be prepared weekly.
5.11.2.4 Antimony stock solution D, ρ[Sb(V)] = 1 000 mg/l.
Dissolve (1,000 ± 0,002) g of pure antimony powder in (10 ± 0,1) ml of concentrated nitric acid (5.8).
Heat the solution to boiling and evaporate off the excess nitric acid.
Perform this procedure carefully under a chemical hood.
Cool and then take up the hydrated antimony(V) oxide in (50 ± 0,5) ml of cold hydrochloric acid (5.3).
Transfer the solution quantitatively to a 1 000 ml volumetric flask and fill up to the mark with water
(5.2).
This standard should be used to prepare a suitable antimony(V) standard to check quantitative recovery
of antimony(V).
The solution is stable for at least six mo
...
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