Evaluation of a modified electrothermal vaporization sample introduction system for the analysis of liquids by inductively coupled plasma atomic emission spectrometry

Abstract

A Perkin-Elmer electrothermal vaporization (ETV) furnace was modified for use as a sample introduction device for inductively coupled plasma atomic emission spectrometry (ICP-AES). The major modification made is the addition of sheath and cooling gas flows. The sheath gas provides a thin sheath layer between the analyte vapour and the wall of the transport tube to prevent vapour condensation, and the cooling gas cools the analyte vapour to promote aggregate formation. Experiments with liquid samples showed that the addition of these gas flows increases the analyte transport efficiency and reduces matrix effects on the transport efficiency. The results also suggest that the carrier gas flow rate affects the peak shape and peak intensity of the copper signal, probably by changing the vaporization rate. With 10 µl sample solution loadings, the detection limits range from 1 to 6 ppb for Cd, Pb, Zn, Mn and Cu, and the precision (relative standard deviation) varies from 3 to 6%. The system is flexible and holds promises for direct solid sample analysis.