On-line speciation analysis of inorganic arsenic in complex environmental aqueous samples by pervaporation sequential injection analysis

Under optimal conditions the proposed PSI method is characterized by a limit of detection, linear calibration range and repeatability for As(III) of 22 μg L−1 (3sblank level criterion), 50-1000 μg L−1 and 3.0% at the 500 μg L−1 level and for As(V) of 51 μg L−1, 100-2000 μg L−1 and 2.6% at the 500 μg L−1 level, respectively. The method was validated with mixed As(III)/As(V) standard aqueous solutions and successfully applied to the determination of As(III) and As(V) in river water samples with elevated content of dissolved organic carbon and suspended particulate matter with no prior sample pretreatment. Excellent relative recoveries ranging from 98% to 104% were obtained for both As(III) and As(V).