ELECTROTHERMAL VAPORIZATION INTERFACE FOR SAMPLE INTRODUCTION IN INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY

An electrothermal vaporisation (ETV) device was developed for inductively coupled plasma mass spectrometry by modifying a commercial graphite furnace unit. A detailed description of the modifications are presented. The new ETV interface is designed to increase sample transport efficiency by converting analyte vapour into micro-particles in the furnace. The characterisation and optimisation of the device are also discussed. Ten consecutive firings of a 30-pg sample of Pb resulted in relative standard deviations (RSD) of 4% for peak-height and 1.6% for peak-area measurements. The absolute detection limit, determined by comparing the response obtained for a 3-μl sample of a 10 ng ml-1 Pb solution in 1% HNO3 with that obtained for blanks containing 1% HNO3 only, was 10 and 14 fg, for a dwell time of 10 μs, for peak area and peak height, respectively. The linear dynamic range for Pb extends over three orders of magnitude, from 300 fg to 300 pg.