Optimization of the electrothermal vaporization conditions for inductively coupled plasma excitation spectrometry: Selective volatilization versus covolatilization approaches

Abstract

A new version of the outlet port of a graphite furnace electrothermal vaporizer (upward streaming system) is described, in which the hot sample vapour is mixed with an auxiliary carrier argon stream of ambient temperature. The operation procedures using carrier volatilization of organic liquids as gas phase additives are also outlined. The selective volatilization and transport efficiency for As, Cd, Hg, Pb, Sb, Se and Zn could be increased by applying sodium thiosulfate as chemical modifier to solution samples with controlled nitric acid content. On the other hand, a near simultaneous vaporization of 16 elements using chlorination with CCl(4) vapour at 2100 degrees C could be performed for a multielement analysis. By wetting the auxiliary carrier argon stream, the linearity of the analytical curves was improved (except for chromium), when applying multielement standards. Linear analytical curves could also be obtained in the presence of alkali and alkaline earth metal matrices in multielement standards using halocarbon assisted electrothermal vaporization sample introduction.