Effect of cathodic electrolyte on the performance of electrochemical hydride generation from graphite cathode

The classic silver diethyldithiocarbamate (SDDC) spectrophotometric procedure for arsenic determination has been used for investigation of the effect of cathodic electrolyte on the performance of electrochemical hydride generation (HG) from graphite cathode. The results of this study show that the presence of a soft metal ion such as Cd(II), Sn(II) and/or Zn(II) in the acidic cathodic electrolyte can increase effectively the efficiency of electrochemical hydride generation and decrease the effect of interferences. The possible mechanisms of these effects have been discussed in detail. The parameters related to the electrochemical hydride generation were investigated. Also the characteristic data of the electrochemical hydride generation and common hydride generation by NaBH4 were compared. Under optimised conditions, the system is selective to As(III) and total inorganic analyses can be performed after a pre-reduction stage prior to electrochemical hydride generation. This will allow the differential determination of inorganic arsenic species. The method is appropriate to the determination of 4–40 μg of each arsenic species.