NF EN ISO 12846
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Water quality - Determination of mercury - Method using atomic absorption spectrometry (AAS) with and without enrichment
ISO 12846:2012 specifies two methods for the determination of mercury in drinking, surface, ground, rain and waste water after appropriate pre-digestion. For the first method, an enrichment step by amalgamation of the Hg on, for example, a gold/platinum adsorber is used. For the second method, the enrichment step is omitted. The choice of method depends on the equipment available, the matrix and the concentration range of interest. Both methods are suitable for the determination of mercury in water. The method with enrichment commonly has a practical working range from 0,01 µg/l to 1 µg/l. The mean limit of quantification (LOQ) reported by the participants of the validation trial was 0,008 µg/l. This information on the LOQ gives the user of ISO 12846:2012 an orientation and does not replace the estimation of performance data from laboratory specific data. It has to be considered that it is possible to achieve lower LOQs with specific instrumentation (e.g. single mercury analysers). The method without enrichment commonly has a practical working range starting at 0,05 µg/l. The LOQ reported by the participants of the validation trial was 0,024 µg/l. It is up to the user, based on the specific application, to decide whether higher concentrations are determined by omitting the enrichment step and/or by diluting the sample(s). The sensitivity of both methods is dependent on the selected operating conditions. Another possibility for the determination of extremely low Hg concentrations down to 0,002 µg/l without pre-concentration is the application of atomic fluorescence spectrometry (see ISO 17852). Specific atomic-absorption mercury analysers allow determinations down to 0,010 µg/l without pre-concentration. In general, the determination of trace concentrations of Hg by AAS (or AFS) is dependent on clean operating conditions in the laboratory and on the use of high-purity chemicals with negligible low-Hg blanks. Note that ISO 12846:2012 may be applied to industrial and municipal waste water after an additional digestion step performed under appropriate conditions and after suitable method validation. A potential sample stability issue (mercury loss) for anaerobic reducing industrial effluents has to be considered thoroughly.
ISO 12846:2012 specifies two methods for the determination of mercury in drinking, surface, ground, rain and waste water after appropriate pre-digestion. For the first method, an enrichment step by amalgamation of the Hg on, for example, a gold/platinum adsorber is used. For the second method, the enrichment step is omitted.
The choice of method depends on the equipment available, the matrix and the concentration range of interest. Both methods are suitable for the determination of mercury in water. The method with enrichment commonly has a practical working range from 0,01 µg/l to 1 µg/l. The mean limit of quantification (LOQ) reported by the participants of the validation trial was 0,008 µg/l. This information on the LOQ gives the user of ISO 12846:2012 an orientation and does not replace the estimation of performance data from laboratory specific data. It has to be considered that it is possible to achieve lower LOQs with specific instrumentation (e.g. single mercury analysers).
The method without enrichment commonly has a practical working range starting at 0,05 µg/l. The LOQ reported by the participants of the validation trial was 0,024 µg/l. It is up to the user, based on the specific application, to decide whether higher concentrations are determined by omitting the enrichment step and/or by diluting the sample(s). The sensitivity of both methods is dependent on the selected operating conditions.
Another possibility for the determination of extremely low Hg concentrations down to 0,002 µg/l without pre-concentration is the application of atomic fluorescence spectrometry (see ISO 17852). Specific atomic-absorption mercury analysers allow determinations down to 0,010 µg/l without pre-concentration.
In general, the determination of trace concentrations of Hg by AAS (or AFS) is dependent on clean operating conditions in the laboratory and on the use of high-purity chemicals with negligible low-Hg blanks.
Note that ISO 12846:2012 may be applied to industrial and municipal waste water after an additional digestion step performed under appropriate conditions and after suitable method validation. A potential sample stability issue (mercury loss) for anaerobic reducing industrial effluents has to be considered thoroughly.
Le présent document s'adresse aux laboratoires ayant à doser le mercure total, à de faibles concentrations dans les eaux.
Le présent document spécifie deux méthodes pour la détermination du mercure. Dans la méthode décrite dans l'Article 4, le chlorure d'étain (II) est utilisé comme réactif de réduction alors que dans celle décrite à l'Article 5, c'est le tétrahydroborate de sodium qui sert de réactif de réduction. Le choix de la méthode dépend de l'équipement disponible et de la matrice (voir Article 3). Les deux méthodes conviennent pour la détermination du mercure dans l'eau, par exemple dans l'eau potable, dans les eaux souterraines, dans les eaux de surface et dans les eaux usées, dans une gamme de concentration de 0,1 microgramme/l à 10 microgrammes/l. Des concentrations plus élevées peuvent être déterminées si l'échantillon est dilué. Si l'on utilise des analyseurs spécifiques du mercure optimisés, il est possible de déterminer de plus faibles concentrations dans la gamme de 0,01 microgramme/l à 1 microgramme/l.
- Avant-proposiv
- Introductionv
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1 Domaine d'application1
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2 Références normatives2
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3 Principe2
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4 Interférences générales3
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5 Prélèvement des échantillons et prétraitement des échantillons d'eau potable, de surface, souterraine et de pluie3
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6 Dosage du mercure après réduction par du chlorure d'étain(II) et enrichissement par amalgame4
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6.1 Réactifs et étalons4
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6.2 Appareillage et instruments7
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6.3 Réglage des instruments9
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6.4 Mode opératoire9
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6.5 Calculs10
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7 Dosage du mercure après réduction par du chlorure d'étain(II) sans enrichissement10
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7.1 Réactifs et étalons10
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7.2 Appareillage et instruments10
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7.3 Prélèvement des échantillons et prétraitement des échantillons d'eau potable, de surface, souterraine et de pluie11
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7.4 Prélèvement des échantillons et prétraitement des échantillons d'eau résiduaire11
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7.5 Réglage des instruments11
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7.6 Mode opératoire11
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7.7 Calculs12
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8 Expression des résultats12
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9 Rapport d'essai12
- Annexe A (informative) Données de performance13
- Bibliographie16
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