Inorganic arsenic speciation in natural mineral drinking waters by flow-through anodic stripping chronopotentiometry

• Speciation of inorganic As forms by ASCP in calibrationless mode described.
• Arsenic species determined in direct analysis without sample preparation step.
• Procedure based on 2 cycles differing in Edep to determine As(III) and total As.
• Method applied to samples even with 5-fold higher content of Cu versus As.

A simple and inexpensive method for chemical speciation of inorganic As in natural mineral drinking waters by using anodic stripping chronopotentiometry (ASCP) in an electrochemical flow-through cell with an Au wire as the working electrode was described in the present work. The presented method is an attractive alternative to laborious and time-consuming procedures requiring pre-separation of various forms of As before their detection by other flow-through and non flow-through stripping methods. The limits of detection were found to be 0.42 µg L−1 for As(III) and 0.55 µg L−1 for As(V), obtained at the deposition potentials of −350 mV and −1600 mV, respectively. The accuracy of the method was assessed by the spiking-and-recovery experiments for particular water samples and the recoveries found, being in range from 99% to 105% for As(III) and from 104% to 106% for As(V), respectively, were quantitative. The proposed method was successfully applied to speciation analysis of inorganic As in water samples with a high content of Cu.

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