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Validation of various vapor generation systems coupled with atomic fluorescence spectrometry for the determination of cadmium-A comparative evaluation of chemical variables, performance characteristics and interferences

Zhongxi Li, Liping Zhou

Various vapor generation systems for the determination of Cd by VG-AS have been evaluated in this paper, includingKBH4-HCl,KBH4-HCl-Co2+- thiourea, KBH4-HCl-Co2+-8-hydroxyquinoline, KBH4-K3Fe(CN)6-HCl- NH2OHHCl and KBH4-HCl-NaIO3 systems. It was found that the optimized chemical parameters for various vapor generation systems were keep at the same levels. The effects of recommendatory enhancers such asCo2+-thiourea,Co2+-8-hydroxyquinoline,K3Fe(CN)6andNaIO3were studied and the results revealed that the enhancers did not improve the vapor generation efficiency of Cd besides thiourea-Co2+. The sensitivities, precisions and detection limits of various vapor generation systems were tested and the use of KBH4-HCl-Co2+-thiourea systemcould obtain higher sensitivity, better precision and detection limits. In addition, the use of thiourea-Co2+, viz, KBH4-HCl-Co2+-thiourea system, could reduce the interferences from some coexisting ions.