STABILITY AND SENSITIVITY ENHANCEMENT USING ETV-ICPMS

The interfacing of an electrothermal vaporization (ETV) unit to an inductively coupled plasma mass spectrometer (ICPMS) produces a powerful system for ultra-low-level compositional analysis of micro-volume samples, as well as decreasing some of the molecular interferences inherent in a conventional-nebulization ICPMS. Some problems still remain with this technique in respect to signal variation, sample heating profiles, and instrument tuning parameters. Advances are presented concerning the instrumental conditions necessary for lowering signal variation. These include optimization of ''dry-plasma'' tuning of the spectrometer lens stack, furnace cooling/heating, and tube mounting. Novel ways of enhancing sensitivity by multiple deposition, preconcentration, and chemical modification have been investigated with particular emphasis on uranium and radium determination.