Determination of ultra trace arsenic species in water samples by hydride generation atomic absorption spectrometry after cloud point extraction

Cloud point extraction (CPE) methodology has successfully been employed for the preconcentration of ultra-trace arsenic species in aqueous samples prior to hydride generation atomic absorption spectrometry (HGAAS). As(III) has formed an ion-pairing complex with Pyronine B in presence of sodium dodecyl sulfate (SDS) at pH 10.0 and extracted into the non-ionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-114). After phase separation, the surfactant-rich phase was diluted with 2 mL of 1 M HCl and 0.5 mL of 3.0% (w/v) Antifoam A. Under the optimized conditions, a preconcentration factor of 60 and a detection limit of 0.008 μg L−1 with a correlation coefficient of 0.9918 was obtained with a calibration curve in the range of 0.03–4.00 μg L−1. The proposed preconcentration procedure was successfully applied to the determination of As(III) ions in certified standard water samples (TMDA-53.3 and NIST 1643e, a low level fortified standard for trace elements) and some real samples including natural drinking water and tap water samples.

The possible complex formation mechanism for ultra-trace As determination.Figure optionsDownload as PowerPoint slideHighlights
► CPE/HGAAS system for arsenic determination and speciation in real samples has been applied first time until now.
► The proposed method has the lowest detection limit when compared with those of similar CPE studies present in literature.
► The linear range of the method is highly wide and suitable for its application to real samples.