Electrochemical hydride generation for the determination of hydride formingelements by atomic fluorescence spectrometry

摘要

The determinations of As,Bi,Ge,Sb and Se were performed by atomic fluorescence spectrometry followingtheir electrochemical hydride generation.An electrochemical hydride generator based on a screw-thread sealarrangement,working in a continuous flow mode was used. The effects of cathode material,shape and areaof material,catholyte,sample flow rate,applied current,catholyte solution concentration and interference oftransition metals on signal intensity were studied. Five kinds of materials including lead,graphite,copper,tungsten and platinum with different shapes were tested as cathode materials.The signal obtained from a 3-dimensional electrode was higher than that from a 2-dimensional electrode under the sameconditions.The signal intensity of Ge in HNO3 medium within a narrow concentration range of 0.05–0.10 mol L1 was stronger than that in other acidic medium, such as HCl and H2SO4.However,the signal intensity of Ge was rapidly decreased with HNO3,HCl and H2SO4 concentration increasing, and then reached approximately zero.In general,limits of detection and a precision were improved using a graphite cathodein H3PO4 medium. The analysis of the reference materials showed good agreement with the certified values for As,Bi,Ge,Sb and Se.The method was successfully applied in the determination of As,Bi,Ge,Sb and Se intraditional Chinese medicine samples.