Flow injection electrochemical hydride generation atomic absorption spectrometry (FI-EHG-AAS) as a simple device for the speciation of inorganic arsenic and selenium

A flow-injection system for the determination of inorganic arsenic [As(III)/As(V)] and selenium species [Se(IV)/ Se(VI)] by electrochemical hydride generation, cryogenic trapping and atomic absorption spectrometry is described. A simple and robust electrochemical flow-through cell with fibrous carbon as cathodic material has been developed for the speciation of arsenic. A cold-trap system makes possible to eliminate interferences from methylated arsenic species. Without pre-reduction the system is selective to As(III) and Se(IV). The selectivity obtained with fibrous carbon as cathode material is compared to the selectivity obtained with a second electrochemical flow-through cell using a lead foil as cathode.