Abstract
Chemical vapor generation of cadmium was optimized in the presence of various additives using atomization in an externally heated quartz tube atomizer and atomic absorption spectrometry. Employing Cr3+/KCN modifiers in a four channel chemical vapor generation system was found to provide the most robust conditions, the highest overall chemical vapor generation efficiency and the lowest limit of detection of 60 pg mL-1 Cd.
The vapor generation system was subsequently connected to an in-house assembled atomic fluorescence spectrometer equipped with a miniature diffusion flame atomizer in order to achieve substantially better sensitivity. The optical path of the spectrometer was optimized as well as the feeding current of an electrodeless discharge lamp used for excitation of atomic fluorescence.
A preliminary evaluation of analytical performance (limit of detection of 3 pg mL-1) revealed that the significant contribution to the measured noise comes from serious contamination from reagents used for chemical vapor generation. Nevertheless, these results promise extremely high sensitivity that is substantially better than that achieved with atomic absorption spectrometry.