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

Preconcentration of multi-element volatile hydrides in a graphite furnace and the subsequent determination by inductively coupled plasma mass spectrometry (ICP-MS) is a relatively new method for elemental analysis. This method offers several advantages over direct hydride generation sample introduction. In this technique the excess hydrogen generated as a by-product of the reduction reaction of the analytes was not introduced into the plasma with the analytes, thus giving the plasma greater 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 by 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 was based on the slope value of the linear portion of the calibration curve. Effectiveness of the trapping method was determined by analysis of a standard reference material.