Comparative studies on chemical modification of polytetrafluoroethylene slurry in ETV-ICP-AES and ETAAS

Abstract

The chemical modification of polytetrafluoroethylene (PTFE) slurry in electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES) and in electrothermal atomic absorption spectrometry (ETAAS) was investigated and compared systematically. For both cases, the graphite furnace can be used as a chemical reactor in which the fluorinating reagent PTFE can convert the oxides of analytes into their volatile fluorides at high temperature. However, different influences resulting from fluorination in ETV-ICP-AES and ETAAS were observed owing to different functions of the graphite furnace in the two techniques. The formation of fluoride enhanced the emission signals of the refractory elements Mo, Cr and Yb significantly in ETV-ICP-AES, but only improved the sensitivity of Cr in ETAAS. In both ETV-ICP-AES and ETAAS, the addition of PTFE increased the maximum ashing temperature of volatile analyte cadmium. Moreover, PTFE can obviously reduce or remove the matrix interference and particle size effects of solid samples; this advantage is a benefit in the analysis of complicated samples, especially for the direct analysis of solid samples.