Hydride generation electrochemical

FLOW INJECTION ELECTROCHEMICAL HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY EOR THE DETERMINATION OE ARSENIC... 

A flow-injection system with electrochemical hydride generation and atomic absorption detection for the determination of arsenic is described. This technique has been developed in order to avoid the use sodium tetrahydroborate, which is capable of introducing contamination. The sodium tetrahydroborate (NaBH ) - acid reduction technique has been widely used for hydride generation (HG) in atomic spectrometric analyses. However, this technique has certain disadvantages. The NaBH is capable of introducing contamination, is expensive and the aqueous solution is unstable and has to be prepared freshly each working day. In addition, the process is sensitive to interferences from coexisting ions. 

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Fig. 55. Flow-cell for electrochemical hydride generation. (Reprinted with permission from Ref. [158].)...

The preferential reduction of the trivalent species in hydride generation can be used for the speciation of As, while the pentavalent species is first reduced by hydrogen after converting it into the trivalent species by a reduction with cystein. A similar way can be followed for SelV and SeV This can be done both in the case of conventional as well as of electrochemical hydride generation [324]. 

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