Arsenic is ubiquitous in the earth’s crust in low concentrations. Elevated levels can be found in mineral deposits and ores. Arsenic from such deposits leaches into the groundwater in the form of arsenite (AsO33-) and arsenate (AsO43-), causing its contamination. In addition to the arsenic originating from natural sources, industry and agriculture contribute to the contamination to a lower extent. The guideline value for inorganic total arsenic in the World Health Organization’s «Guidelines for Drinking-water Quality» is set to 10 μg/L.
With a limit of detection (LOD) of 0.9 μg/L, anodic stripping voltammetry is a viable, less sophisticated alternative to atomic absorption spectroscopy (AAS) for the determination of arsenic. While AAS (and competing methods) can only be performed in a laboratory, anodic stripping voltammetry can be used conventionally in the laboratory or alternatively in the field using the 946 Portable VA Analyzer. The determination is carried out on the scTRACE Gold electrode.
Bottled mineral water
The scTRACE Gold is electrochemically activated prior to the first determination. In the next step, the water sample and the supporting electrolyte are pipetted into the measuring vessel. The determination of arsenic is carried out with the 884 Professional VA or with the 946 Portable VA Analyzer using the parameters specified in Table 1. The concentration is determined by two additions of an arsenic standard addition solution.
|Mode||SQW – Square wave|
|Deposition potential||-1 V|
|Deposition time||60 s|
|Start potential||-0.3 V|
|End potential||0.4 V|
|Peak potential As||0V|
- scTRACE Gold
With a 60 s deposition time, this method is suitable for the determination of arsenic in water samples in concentrations from β(As(total)) = 0.9–10 μg/L.
|Bottled mineral water||4.4|
Application Bulletin 416: Determination of arsenic in water with the scTRACE Gold