GRAPHITE-FURNACE HYDRIDE PRECONCENTRATION AND SUBSEQUENT DETECTION BYINDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

Preconcentration of multi-element volatile hydrides in a graphite furn ace and the subsequent determination by inductively coupled plasma mas s spectrometry (ICP-MS) is a relatively new method for elemental analy sis. This method offers several advantages over direct hydride generat ion sample introduction. In this technique the excess hydrogen generat ed as a by-product of the reduction reaction of the analytes was not i ntroduced into the plasma with the analytes, thus giving the plasma gr eater stability. The hydrides of arsenic, bismuth, and tellurium were trapped in the presence of metallic palladium inside the graphite tube of an electrothermal vaporization unit, and subsequently determined b y the ICP-MS in a single run. The linearity obtained using this method was limited to a sub-ng/ml concentration range. The preliminary limit of detection calculated for arsenic is 0.002 ng ml(-1), this value wa s based on the slope value of the linear portion of the calibration cu rve. Effectiveness of the trapping method was determined by analysis o f a standard reference material.