Hydride generation (CHG) is a well-established technique for determination of toxic arsenic (As) [1]. Electrochemical hydride generation (ECHG) has been introduced as a suitable alternative to common hydride generation by NaBH4, and has been shown, to be capable of circumventing some of the disadvantages associated with the NaBH4-acid reducing system [2]. This paper describes a novel method for the quantitative determination of arsenic in food and environmental samples. The method is based on electrochemical reduction of As to Arsine (AsH3) in an electrochemical cell and subsequent reaction of AsH3 with silver diethyldithiocarbamate to give an absorbing complex at 525 nm. The electrochemical generator consisted of a cathode cell separated from the anode cell by a nafion ion exchange membrane. Arsine is generated at the cathode and reacts with silver diethyldithiocarbamate in a headspace microfunnel. The affecting parameters on the efficiency of the electrochemical hydride generation and the microextraction steps have been examined and optimized. The analytical performance of the method has been evaluated under optimized operating condition (graphite cathode, 150 mA current, 0.3 M H2SO4 as catholyte, 10 min for reaction duration) and the analytical figures of merits has been reported. As advantage, the system is very fast, efficient and environmentally friendly for monitoring total arsenic food and waters.

Keywords