ISO 5666-2:1983
(Main)Water quality — Determination of total mercury by flameless atomic absorption spectrometry — Part 2: Method after pretreatment with ultraviolet radiation
Water quality — Determination of total mercury by flameless atomic absorption spectrometry — Part 2: Method after pretreatment with ultraviolet radiation
Qualité de l'eau — Dosage du mercure total par spectrométrie d'absorption atomique sans flamme — Partie 2: Méthode après minéralisation par irradiation aux rayons ultraviolets
Kakovost vode - Ugotavljanje skupnega živega srebra z atomsko absorpcijsko spektrometrijo (tehnika hladnih par) - 2. del: Metoda po pripravi vzorca z obsevanjem z ultravijoličnimi žarki
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International Standard @ 566612
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INTE RNATlOhAL ORCANIZATlOh FOR STAhDARDiZATiO~*ME~LlYrlAPO~~AR OPïArlU3AUMR no CTAHLlAPTH3AUHH*ORGANlSATlON INTERNATlOhALE DE NDRMALISATiOh
Water quality - Determination of total mercury by
f lameless atomic absorption spectrometry -
Part 2 : Method after pretreatment with ultraviolet
radiation
Qualité de l'eau - Dosage du mercure total par spectrométrie d'absorption atomique sans flamme - Partie 2 : Méthode après
minéralisation par irradiation aux rayons ultraviolets
First edition - 1983-07-01
Ref. Noi IS0 5666/2-.I983 (E)
UDC 614.777 : 543.422 : 546.49
Descriptors : water, quality, tests, determination of content, mercury, ultraviolet radiation tests, water pollution.
Price based on 8 pages
---------------------- Page: 1 ----------------------
F d reword
IS0 (the International Organization for Standardization) is a worldwide federation of
nati na1 standards bodies (IS0 member bodies). The work of developing International
Sta dards is carried out through IS0 technical committees. Every member body
inte sted in a subject for which a technical committee has been authorized has the
righ to be represented on that committee. International organizations, governmental
and on-governmental, in liaison with ISO, also take part in the work.
t
Dra International Standards adopted by the technical committees are circulated to
the ember bodies for approval before their acceptance as International Standards by
the I O Council.
t
tional Standard IS0 5666/2 was developed by Technical Committee
147, Water qualify, and was circulated to the member bodies in December
C
een approved by the member bodies of the following countries :
Australia
Germany, F.R. Romania
Belgium Hungary South Africa, Rep. of
Brazil India
Spain
Canada Italy Sweden
Chile Mexico
Switzerland
Czechoslovakia Netherlands United Kingdom
Egypt, Arab Rep. of
New Zealand USSR
France Poland
ber body of the following country expressed disapproval of the document on
Japan
O International Organization for Standardization, 1983 O
Printed in Switzerland
---------------------- Page: 2 ----------------------
IS0 5666/2-1983 (E)
INTERNATIONAL STANDARD
Water quality - Determination of total mercury by
flameless atomic absorption spectrometry -
Part 2 : Method after pretreatment with ultraviolet
radiation
O Introduction 3 Principle
This document constitutes the second part of an International Pretreatment of a test portion by exposure to ultraviolet
Standard specifying methods for the determination of total radiation for a period of 10 min, in order to decompose organic
mercury in water by flameless atomic absorption spectrometry. matter and organic mercury compounds and to convert all the
mercury present to mercury(l1).
Since various types of water may be tested for the presence of
pii)
mercury, it has been considered preferable to standardize Reduction of mercury(l1) to metallic mercury by tin(ll) chloride.
several methods of determination, which, although they are all
based on the same instrumental technique (atomic absorption Entrainment of the mercury in a current of gas and determina-
spectrometry), involve, nevertheless, sufficiently important tion of the mercury, as the monatomic vapour, by flameless
procedural differences so that their respective fields of applica- atomic absorption spectrometry at a wavelength of 253,7 nm.
tion differ significantly.
Thus, this part (part 2) specifies a method of determination
4 Reagents
after pretreatment with ultraviolet radiation and is applicable to
drinking water and to water used for food and drink processing. During the analysis, use only the water (4.1) and reagents of
recognized analytical quality, the mercury contents of which
Part 1 specifies a method of determination after digestion with are as low as possiblel).
permanganate-peroxodisulfate and is applicable, in particular,
to surface waters and domestic and industrial wastewaters.
Demineralized-distilled water, or water of equivalent
4.1
Part 3, at present under study, will specify a method of deter-
quality, free from mercury.
mination after digestion with bromine and will apply to soft
waters and brines, to drinking water and to other types of water
4.2 Sulfuric acid, ez0 = 1,84 g/ml.
containing only small amounts of organic matter.
Each of the three parts describes the method in its entirety and
4.3 Nitric acid, ez0 = 1.42 g/ml.
a
can therefore be used independently of the others.
Hydrochloric acid, e20 = 1,19 g/ml.
4.4
1
Scope and field of application
4.5 Hydrochloric acid, approximately 0,3 mol/l solution.
This part of IS0 5666 specifies a flameless atomic absorption
Dilute 10 rnl of the hydrochloric acid (4.4) to 1 litre with water.
spectrometric method for the determination of total mercury in
drinking water and in water used for food and drink processing.
4.6 Tin(l1) chloride, solution containing 100 g of
SnCI2.2H2O per litre.
The method permits determination of as little as 0,02 pg of mer-
cury in the test portion used for the analysis. For a test portion
Prepare this solution on the day of use by one of the following
of volume 100 ml, the lower limit of determination is 0,2 pg/l.
two methods :
a) Dissolve 25 g of tin(ll) chloride dihydrate in 50 ml of
warm hydrochloric acid (4.4). If cloudy, filter and add a
2 Reference
small granule of tin to the filtrate. Cool and transfer quan-
titatively to a 250 ml one mark volumetric flask. Dilute to the
IS0 5725, Precision of test methods - Determination of
mark with water and mix.
repeatability and reproducibility by inter-laboratory tests.
1) If the reagents used lead to high results in blank tests, it is necessary to use products of better quality.
---------------------- Page: 3 ----------------------
IS0 5666/2-1983 (E)
5.1 Atomic absorption spectrometer, provided with a low
b) Dissolve, by heating in a boiling water bath, 13 g of tin
pressure mercury lamp (or a hollow-cathode mercury lamp), or
in 50 ml of the hydrochloric acid (4.4). Cool, transfer quan-
a mercury vapour analyser.
titatively to a 250 ml one-mark volumetric flask, dilute to the
mark with water and mix.
5.2 Recorder, with a maximum signal indicator or a peak
Eliminate any mercury which may be present in this solution by
area integrator (see note to 5.9).
bubbling nitrogen through it (for example during 30 min).
5.3 Immersion-type ultraviolet lamp, medium or low
4.7 Potassium dichromate, 4 g/l acidic solution.
pressure.1)
Dissolve 4 g of potassium dichromate (K2Cr207) in 500 ml of
NOTES
water and carefully add either 500 ml of the sulfuric acid (4.2) or
1 With the medium pressure lamps, sample cooling is essential either
500 ml of the nitric acid (4.3).
by means of an ice bath or using a water jacket through which chilled
water is circulated around the irradiation vessel. In addition, some
4.8 Mercury, standard solution corresponding to 1 g of Hg lamps require gas cooling as specified by the manufacturer. Some
lamps will not relight for up to 20 min after being switched off and are
per litre.
best left switched on continuously during the tests.
Weigh, to the nearest 0,001 g, 1,354 g of mercury(l1) chloride
2 Ultraviolet radiation is harmful to the skin and especially to the
(HgCI,), transfer to a 1 O00 ml one-mark volumetric flask and eyes. The lamps should be operated only when covered by an amber
dissolve in about 25 ml of the hydrochloric acid (4.4). Dilute to glass screen.
1 ml of this standard solution
the mark with water and mix.
contains 1 mg of Hg.
5.4 Irradiation vessels, of glass capable of containing at
least 100 ml of sample and suitable for use with the UV lamp to
This solution can be stored in borosilicate glass bottles for
be used. Suitable types of equipment are shown in figures 1, 2
about 1 month.
and 3.
NOTE - This solution can be stabilized by adding 50 ml of the acidic
NOTE - The irradiation vessels should be designed so that the solu-
potassium dichromate solution (4.7) before diluting to the mark.
tion is exposed to the whole of the quartz window of the lamp. The ef-
ficiency of irradiation is closely dependent on effective mixing. A
250 ml measuring cylinder is the most suitable vessel for use with the
Mercury, standard solution corresponding to 10 mg of
4.9
Hanau lamps; its effectiveness is greatly increased by providing a loop
Hg per litre.
between the bottom of the cylinder and the liquid surface which allows
the magnetic stirrer to act as a circulation pump. The Hanovia lamps
Dilute 10,O ml of the standard mercury solution (4.8) to 1 O00 ml
require special irradiation vessels, but the same principles apply.
with the hydrochloric acid solution (4.5).
It is essential that the combination of the UV lamp and the irradiation
vessels be checked before use to ensure that complete destruction of
1 ml of this standard solution contains 10 pg of Hg.
organic mercury compounds occurs in an acceptably short time. As
the lamp ages, repeat checks should be carried out to confirm that the
Prepare this solution on the day of use.
time initially established is still valid la method of control is described in
annex 6).
4.10 Mercury, standard solution corresponding to O, 1 mg of
Hg per litre.
5.5 Aeration flasks.
Dilute 10.0 ml of the standard mercurysolution (4.9) to 1 O00 ml
The aeration may be carried out in the irradiation vessel if it has
with the hydrochloric acid solution (4.5).
a suitable shape. If not, the irradiated solution should be
transferred to a tall form aeration flask, of volume appropriate
1 ml of this standard solution contains 0,l pg of Hg.
to the size of the test portion, compatible with the rest of the
apparatus, bearing a calibration mark corresponding to the op-
Prepare this solution on the day of use.
timum filling level, the dead volume of which has been reduced
to a minimum and through which the gas flows under the op-
timum conditions. For this, the aeration tube should be design-
5 Apparatus ed with a finely drawn out point, a sphere pierced with holes or
a fritted end (pores of 100 to 250 pm). It is necessary to confirm
Before use, all glassware shall be washed very carefully with that the
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.RUSFLMVNRQualité de l'eau -- Dosage du mercure total par spectrométrie d'absorption atomique sans flamme -- Partie 2: Méthode après minéralisation par irradiation aux rayons ultravioletsWater quality -- Determination of total mercury by flameless atomic absorption spectrometry -- Part 2: Method after pretreatment with ultraviolet radiation13.060.50VQRYLExamination of water for chemical substancesICS:Ta slovenski standard je istoveten z:ISO 5666-2:1983SIST ISO 5666-2:1997en01-januar-1997SIST ISO 5666-2:1997SLOVENSKI
STANDARD
SIST ISO 5666-2:1997
International Standard @ 566612 -~ ~ INTE RNATlOhAL ORCANIZATlOh FOR STAhDARDiZATiO~*ME~LlYrlAPO~~AR OPïArlU3AUMR no CTAHLlAPTH3AUHH*ORGANlSATlON INTERNATlOhALE DE NDRMALISATiOh Water quality - Determination of total mercury by f lameless atomic absorption spectrometry - Part 2 : Method after pretreatment with ultraviolet radiation Qualité de l'eau - Dosage du mercure total par spectrométrie d'absorption atomique sans flamme - Partie 2 : Méthode après minéralisation par irradiation aux rayons ultraviolets First edition - 1983-07-01 Ref. Noi IS0 5666/2-.I983 (E) UDC 614.777 : 543.422 : 546.49 Descriptors : water, quality, tests, determination of content, mercury, ultraviolet radiation tests, water pollution. Price based on 8 pages SIST ISO 5666-2:1997
F d reword IS0 (the International Organization for Standardization) is a worldwide federation of nati na1 standards bodies (IS0 member bodies). The work of developing International Sta dards is carried out through IS0 technical committees. Every member body inte sted in a subject for which a technical committee has been authorized has the righ to be represented on that committee. International organizations, governmental and on-governmental, in liaison with ISO, also take part in the work. t Dra International Standards adopted by the technical committees are circulated to the ember bodies for approval before their acceptance as International Standards by the I O Council. t tional Standard IS0 5666/2 was developed by Technical Committee C 147, Water qualify, and was circulated to the member bodies in December een approved by the member bodies of the following countries : Australia Germany, F.R. Romania Belgium Hungary South Africa, Rep. of Brazil India Spain Canada Italy Sweden Chile Mexico Switzerland Czechoslovakia Netherlands United Kingdom Egypt, Arab Rep. of New Zealand USSR France Poland ber body of the following country expressed disapproval of the document on Japan O International Organization for Standardization, 1983 O Printed in Switzerland SIST ISO 5666-2:1997
INTERNATIONAL STANDARD IS0 5666/2-1983 (E) Water quality - Determination of total mercury by flameless atomic absorption spectrometry - Part 2 : Method after pretreatment with ultraviolet radiation O Introduction This document constitutes the second part of an International Standard specifying methods for the determination of total mercury in water by flameless atomic absorption spectrometry. Since various types of water may be tested for the presence of mercury, it has been considered preferable to standardize several methods of determination, which, although they are all based on the same instrumental technique (atomic absorption spectrometry), involve, nevertheless, sufficiently important procedural differences so that their respective fields of applica- tion differ significantly. Thus, this part (part 2) specifies a method of determination after pretreatment with ultraviolet radiation and is applicable to drinking water and to water used for food and drink processing. Part 1 specifies a method of determination after digestion with permanganate-peroxodisulfate and is applicable, in particular, to surface waters and domestic and industrial wastewaters. Part 3, at present under study, will specify a method of deter- mination after digestion with bromine and will apply to soft waters and brines, to drinking water and to other types of water containing only small amounts of organic matter. Each of the three parts describes the method in its entirety and can therefore be used independently of the others. pii) a 1 Scope and field of application This part of IS0 5666 specifies a flameless atomic absorption spectrometric method for the determination of total mercury in drinking water and in water used for food and drink processing. The method permits determination of as little as 0,02 pg of mer- cury in the test portion used for the analysis. For a test portion of volume 100 ml, the lower limit of determination is 0,2 pg/l. 2 Reference IS0 5725, Precision of test methods - Determination of repeatability and reproducibility by inter-laboratory tests. 3 Principle Pretreatment of a test portion by exposure to ultraviolet radiation for a period of 10 min, in order to decompose organic matter and organic mercury compounds and to convert all the mercury present to mercury(l1). Reduction of mercury(l1) to metallic mercury by tin(ll) chloride. Entrainment of the mercury in a current of gas and determina- tion of the mercury, as the monatomic vapour, by flameless atomic absorption spectrometry at a wavelength of 253,7 nm. 4 Reagents During the analysis, use only the water (4.1) and reagents of recognized analytical quality, the mercury contents of which are as low as possiblel). 4.1 quality, free from mercury. Demineralized-distilled water, or water of equivalent 4.2 Sulfuric acid, ez0 = 1,84 g/ml. 4.3 Nitric acid, ez0 = 1.42 g/ml. 4.4 Hydrochloric acid, e20 = 1,19 g/ml. 4.5 Hydrochloric acid, approximately 0,3 mol/l solution. Dilute 10 rnl of the hydrochloric acid (4.4) to 1 litre with water. 4.6 Tin(l1) chloride, solution containing 100 g of SnCI2.2H2O per litre. Prepare this solution on the day of use by one of the following two methods : a) Dissolve 25 g of tin(ll) chloride dihydrate in 50 ml of warm hydrochloric acid (4.4). If cloudy, filter and add a small granule of tin to the filtrate. Cool and transfer quan- titatively to a 250 ml one mark volumetric flask. Dilute to the mark with water and mix. 1) If the reagents used lead to high results in blank tests, it is necessary to use products of better quality. SIST ISO 5666-2:1997
IS0 5666/2-1983 (E) b) Dissolve, by heating in a boiling water bath, 13 g of tin in 50 ml of the hydrochloric acid (4.4). Cool, transfer quan- titatively to a 250 ml one-mark volumetric flask, dilute to the mark with water and mix. Eliminate any mercury which may be present in this solution by bubbling nitrogen through it (for example during 30 min). 4.7 Potassium dichromate, 4 g/l acidic solution. Dissolve 4 g of potassium dichromate (K2Cr207) in 500 ml of water and carefully add either 500 ml of the sulfuric acid (4.2) or 500 ml of the nitric acid (4.3). 4.8 per litre. Weigh, to the nearest 0,001 g, 1,354 g of mercury(l1) chloride (HgCI,), transfer to a 1 O00 ml one-mark volumetric flask and dissolve in about 25 ml of the hydrochloric acid (4.4). Dilute to the mark with water and mix. 1 ml of this standard solution contains 1 mg of Hg. Mercury, standard solution corresponding to 1 g of Hg This solution can be stored in borosilicate glass bottles for about 1 month. NOTE - This solution can be stabilized by adding 50 ml of the acidic potassium dichromate solution (4.7) before diluting to the mark. 4.9 Hg per litre. Dilute 10,O ml of the standard mercury solution (4.8) to 1 O00 ml with the hydrochloric acid solution (4.5). Mercury, standard solution corresponding to 10 mg of 1 ml of this standard solution contains 10 pg of Hg. Prepare this solution on the day of use. 4.10 Hg per litre. Dilute 10.0 ml of the standard mercurysolution (4.9) to 1 O00 ml with the hydrochloric acid solution (4.5). 1 ml of this standard solution contains 0,l pg of Hg. Prepare this solution on the day of use. Mercury, standard solution corresponding to O, 1 mg of 5 Apparatus Before use, all glassware shall be washed very carefully with the acidic potassium dichromate solution (4.71, and then rinsed several times with water (4.1). Never dry the glassware between two operations. 5.1 Atomic absorption spectrometer, provided with a low pressure mercury lamp (or a hollow-cathode mercury lamp), or a mercury vapour analyser. 5.2 area integrator (see note to 5.9). 5.3 Immersion-type ultraviolet lamp, medium or low pressure.1) NOTES 1 With the medium pressure lamps, sample cooling is essential either by means of an ice bath or using a water jacket through which chilled water is circulated around the irradiation vessel. In addition, some lamps require gas cooling as specified by the manufacturer. Some lamps will not relight for up to 20 min after being switched off and are best left switched on continuously during the tests. 2 Ultraviolet radiation is harmful to the skin and especially to the eyes. The lamps should be operated only when covered by an amber glass screen. Recorder, with a maximum signal indicator or a peak 5.4 Irradiation vessels, of glass capable of containing at least 100 ml of sample and suitable for use with the UV lamp to be used. Suitable types of equipment are shown in figures 1, 2 and 3. NOTE - The irradiation vessels should be designed so that the solu- tion is exposed to the whole of the quartz window of the lamp. The ef- ficiency of irradiation is closely dependent on effective mixing. A 250 ml measuring cylinder is the most suitable vessel for use with the Hanau lamps; its effectiveness is greatly increased by providing a loop between the bottom of the cylinder and the liquid surface which allows the magnetic stirrer to act as a circulation pump. The Hanovia lamps require special irradiation vessels, but the same principles apply. It is essential that the combination of the UV lamp and the irradiation vessels be checked before use to ensure that complete destruction of organic mercury compounds occurs in an acceptably short time. As the lamp ages, repeat checks should be carried out to confirm that the time initially established is still valid la method of control is described in annex 6). 5.5 Aeration flasks. The aeration may be carried out in the irradiation vessel if it has a suitable shape. If not
...
Norme internationale @ 566612
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MEMiYHAPOiiHAR OPrAHH3AUHR il0 CTAHLiAPTM3AUHH*ORGANlSATlON INTERNATIONALE DE NORMALISATION
Qualité de l'eau - Dosage du mercure total par
spectrométrie d'absorption atomique sans flamme -
Partie 2 : Méthode après minéralisation par irradiation aux
rayons ultraviolets
Water quality - Determination of total mercury by flameless atomic absorption spectrometry - Part 2 : Method after
pretreatment with ultraviolet radiation
Premiere édition - 1983-07-01
CDU 614.777 : 543.422 : 546.49
RBf. no : IS0 5666/2-1983 (FI
Descripteurs : eau, qualité, essai, dosage, mercure, essai au rayonnement ultraviolet, pollution de l'eau.
Prix basé sur 8 pages
---------------------- Page: 1 ----------------------
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale
d'organismes nationaux de normalisation (comités membres de I'ISO). L'élaboration
des Normes internationales est confiée aux comités techniques de IWO. Chaque
comité membre intéressé par une étude a le droit de faire partie du comité technique
correspondant. Les organisations internationales, gouvernementales et non gouverne-
e
mentales, en liaison avec I'ISO, participent également aux travaux.
Les projets de Normes internationales adoptés par les comités techniques sont soumis
aux comités membres pour approbation, avant leur acceptation comme Normes inter-
nationales par le Conseil de I'ISO.
La Norme internationale IS0 5666/2 a été élabarée par le comité technique
ISO/TC 147, Qualité de l'eau, et a été soumise aux comités membres en décembre
1981.
Les comités membres des pays suivants l'ont approuvée :
Afrique du Sud, Rép. d' Espagne Pologne
Allemagne, R.F. France Roumanie
Hongrie Royaume-Uni
Australie
Belgique Inde Suède
Brésil Italie Suisse
Mexique Tchécoslovaquie
Canada
Chili Nouvelle-Zélande URSS
Égypte, Rép. arabe d' Pays-Bas
Le comité membre du pays suivant l'a désapprouvée pour des raisons techniques :
0 Organisation internationale de normalisation, 1983 0
Imprimé en Suisse
---------------------- Page: 2 ----------------------
NORM E INTER NAT1 O NALE IS0 5666/2-1983 (FI
Qualité de l'eau - Dosage du mercure total par
spectrométrie d'absorption atomique sans flamme -
Partie 2 : Méthode après minéralisation par irradiation aux
rayons u It raviolets
O Introduction La méthode permet de doser jusqu'à 0,02 pg de mercure dans
la prise d'essai soumise au dosage; pour une prise d'essai de
0'
100 ml, la teneur inférieure dosable sera de 0,2 pg/l.
Le présent document constitue la deuxième partie d'une Norme
internationale spécifiant des méthodes de dosage du mercure
total dans les eaux par spectrométrie d'absorption atomique
sans flamme.
2 Référence
Compte tenu de la variété des types d'eau dans lesquels peut
IS0 5725, Fidélité des méthodes d'essai - Détermination de la
être recherchée la présence de mercure, il est apparu opportun
répétabilité et de la reproductibilité par essais interlaboratoires.
de normaliser plusieurs méthodes de dosage, qui, si elles sont
toutes basées sur la même technique instrumentale ispectro-
métrie d'absorption atomique), présentent néanmoins des dif-
3 Principe
férences suffisamment importantes au niveau de leur mode
opératoire pour que leurs domaines d'application respectifs dif-
Minéralisation d'une prise d'essai par irradiation aux rayons
fèrent sensiblement.
ultraviolets, durant 10 min, afin de détruire la matière organique
et les composés organomercuriques et d'amener tout le mer-
Ainsi la présente partie (partie 2) spécifie une méthode de
cure à l'état de mercure(l1).
dosage après minéralisation par irradiation aux rayons ultravio-
lets applicable aux eaux potables et aux eaux destinées à la pro-
Réduction du mercure(l1) à l'état de métal par le chlorure
duction d'eau d'alimentation.
d'étain(ll1.
La partie 1 spécifie une méthode de dosage après minéralisation
Entraînement du mercure par un courant gazeux et dosage, à
au permangante-peroxodisulfate applicable en particulier aux
l'état de vapeur monoatomique, par spectrométrie d'absorption
eaux de surface et aux eaux résiduaires domestiques et indus-
e atomique sans flamme, à la longueur d'onde de 253,7 nm.
trielles.
La partie 3, encore en cours d'étude, spécifie une méthode de
4 Réactifs
dosage après minéralisation au brome applicable aux eaux dou-
ces et salées, aux eaux potables et autres eaux peu chargées en
Au cours de l'analyse, utiliser uniquement de l'eau (4.1) et des
matières organiques.
réactifs de qualité analytique reconnue, dont la teneur en mer-
cure est aussi faible que possiblel).
Chacune de ces trois parties présente une méthode décrite
dans son intégralité et peut donc être utilisée indépendamment
4.1 Eau déminéralisée puis distillée, ou eau de pureté au
des autres.
moins équivalente, exempte de mercure.
1 Objet et domaine d'application
4.2 Acide sulfurique, @a = 1,84 g/ml.
La présente partie de 1'1S0 5666 spécifie une méthode par spec-
4.3 Acide nitrique, Q~~ = 1,42 g/ml.
trométrie d'absorption atomique sans flamme pour le dosage
du mercure total dans les eaux potables et les eaux destinées à
la production d'eau alimentaire.
4.4 Acide chlorhydrique, Q~~ = 1,19 g/ml.
1) Si les réactifs utilisés conduisent à des blancs élevés, il convient d'employer des produits de qualité supérieure.
1
---------------------- Page: 3 ----------------------
IS0 5666/2-1983 (FI
4.10 Mercure, solution étalon correspondant à 0,l mg de
4.5 Acide chlorhydrique, solution à environ 0,3 mol/l.
Hg par litre.
Diluer 10 ml d'acide chlorhydrique (4.4) à 1 litre avec de l'eau.
Diluer 10,O ml de la solution étalon de mercure (4.9) avec de la
solution d'acide chlorhydrique (4.5) et compléter à 1 000 ml
Chlorure d'étain(ll1, solution à 100 g de SnCI2.2H2O par
4.6
avec cette solution.
litre.
1 ml de cette solution étalon contient 0,l pg de Hg.
Préparer cette solution le jour même de son utilisation de l'une
des deux manières suivantes :
Préparer cette solution le jour même de son utilisation.
a) Dissoudre 25 g de chlorure d'étain(l1) dihydraté dans
50 ml d'acide chlorhydrique (4.4) chaud. S'il y a trouble, fil-
5 Appareillage
trer et ajouter un petit grain d'étain au filtrat. Refroidir et
transférer quantitativement dans une fiole jaugée à un trait
Avant toute utilisation, la verrerie doit être très soigneusement
de 250 ml. Compléter au volume avec de l'eau et homogé-
lavée à l'aide de la solution acide de dichromate de potassium
néiser.
(4.71, puis rincée plusieurs fois à l'eau (4.1).
b) Dissoudre, en chauffant dans un bain d'eau bouillante,
Ne jamais sécher la verrerie entre deux opérations.
13 g d'étain dans 50 ml d'acide chlorhydrique (4.4). Refroi-
dir, transvaser quantitativement la solution dans une fiole
Matériel courant de laboratoire, et
jaugée à un trait de 250 ml, compléter au volume avec de
l'eau et homogénéiser.
5.1 Spectromètre d'absorption atomique, muni d'une
lampe à vapeur de mercure basse pression (ou d'une lampe à
Éliminer le mercure éventuel de cette solution par barbotage
cathode creuse au mercure), ou analyseur de vapeur de mer-
d'azote (par exemple durant 30 min).
cure.
4.7 Dichromate de potassium, solution acide à 4 g/l.
5.2 Enregistreur, muni d'un indicateur à maximum de dévia-
tion ou d'un intégratedr de surface (voir la note de 5.9).
Dissoudre 4 g de dichromate de potassium (K2Cr207) dans
500 ml d'eau et ajouter avec précaution soit 500 ml d'acide sul-
500 ml d'acide nitrique (4.3).
furique (4.21, soit
5.3 Lampe à ultraviolet (UV), du type à immersion, à
moyenne ou basse pression.1)
Mercure, solution étalon correspondant à 1 g de Hg par
4.8
NOTES
litre.
1 Avec les lampes à moyenne pression, il est indispensable de prévoir
Pe$er, à 0,001 g près, 1,354 g de chlorure de mercureill)
le refroidissement de l'échantillon, soit dans un bain de glace, soit en
(HgCI,), l'introduire dans une fiole jaugée à un trait de 1 O00 ml
équipant le récipient d'irradiation d'une chemise de circulation d'eau
et le dissoudre dans environ 25 ml d'acide chlorhydrique (4.4). froide. De plus, certaines lampes requièrent un refroidissement au gaz
comme spécifié par le fabricant.
Compléter au volume avec de l'eau et homogénéiser.
D'autres ne se rallument pas, même 20 min après la coupure du cou-
Cette solution peut être conservée dans des flacons en verre
rant. II est alors préférable de les laisser continuellement allumées pen-
borosilicaté pendant environ 1 mois.
dant les essais.
2 Le rayonnement UV est dangereux pour la peau et tout particulière-
1 ml de cette solution étalon contient 1 mg de Hg.
ment pour les yeux. N'allumer les lampes que lorsqu'elles sont voilées
d'un écran en verre brun.
NOTE - Cette solution peut être stabilisée par addition de 50 ml de la
solution acide de dichromate de potassium (4.7) avant de compléter au
5.4 Vases d'irradiation, en verre, pouvant contenir au
volume avec de l'eau.
moins 100 ml d'échantillon et adaptés à la lampe UV utilisée.
Des exemples de dispositifs d'irradiation sont représentés aux
Mercure, solution étalon correspondant à 10 mg de Hg
4.9
figures 1, 2 et 3.
par litre.
NOTE - Les vases d'irradiation doivent être conçus de manière que la
Diluer 10,O ml de la solution étalon de mercure (4.8) avec de la
solution couvre toute la fenêtre en quartz de la lampe.
solution d'acide chlorhydrique (4.5) et compléter à 1 O00 ml
Le rendement de l'exposition dépend étroitement de l'efficacité de
avec cette solution.
l'agitation.
1 ml de cette solution étalon contient 10 pg de Hg.
Ainsi le rendement obtenu en éprouvette graduée de 250 ml (récipient
convenant le mieux aux lampes Hanau) est considérablement aug-
Préparer cette solution le jour même de son utilisation. menté en prévoyant une boucle entre le fond de l'éprouvette et la sur-
à moyenne pression Hanau TQ 150 et TQ 150/23, Hanovia PCRlL et la lampe à basse pression Hanau TNN 15/32 donnent
Les lampes
1)
satisfaction.
2
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IS0 5666/2-1983 (FI
face du liquide, permettant à l'agitateur magnétique d'agir comme une 7 Mode opératoire
pompe de circulation. Les lampes Hanovia nécessitent des vases dirra-
diation spécifiques, mais les mêmes principes sont applicables.
7.1 Prise d'essai
II est indispensable de vérifier, avant toute utilisation, que le dispositif
d'irradiation détruit bien les composés organomercuriques en un temps
Prélever une prise d'essai de 100 ml de l'échantillon (chapitre 6)
raisonnablement court. Au cours du vieillissement de la lampe, procé-
préalablement homogénéisé.
der à des contrôles destinés à vérifier que la durée d'irradiation établie
initialement reste toujours valable (une méthode de contrôle est décrite
dans l'annexe €3).
7.2 Étalonnage
Préparer au moment de l'emploi, à partir des solution étalons
5.5 Flacons dégazeurs.
de mercure (4.9 et 4.101, au moins cin
...
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