Preconcentration and determination of ultra trace amounts of arsenic(III) and arsenic(V) in tap water and total arsenic in biological samples by cloud point extraction and electrothermal atomic absorption spectrometry

Total inorganic arsenic(III, V) was extracted similarly after oxidation of As(III) to As(V) with KMnO4. As(III) was calculated by difference. After optimization of the extraction condition and the instrumental parameters, a detection limit (3σB) of 0.01 μg l−1 with enrichment factor of 52.5 was achieved for only 10 ml of sample. The analytical curve was linear in the concentration range of 0.02-0.35 μg l−1. Relative standard deviations were lower than 5%. The method was successfully applied to the determination of As(III) and As(V) in tap water and total arsenic in biological samples (hair and nail).