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

The chemical modification of polytetrafluoroethylene (PTFE) slurry in elect rothermal vaporization inductively coupled plasma atomic emission spectrome try (ETV-ICP-AES) and in electrothermal atomic absorption spectrometry (ETA AS) was investigated and compared systematically. For both cases, the graph ite furnace can be used as a chemical reactor in which the fluorinating rea gent PTFE can convert the oxides of analytes into their volatile fluorides at high temperature. However, different influences resulting from fluorinat ion in ETV-ICP-AES and ETAAS were observed owing to different functions of the graphite furnace in the two techniques. The formation of fluoride enhan ced the emission signals of the refractory elements Mo, Cr and Yb significa ntly in ETV-ICP-AES, but only improved the sensitivity of Cr in ETAAS. In b oth ETV-ICP-AES and ETAAS, the addition of PTFE increased the maximum ashin g temperature of volatile analyte cadmium. Moreover, PTFE can obviously red uce or remove the matrix interference and particle size effects of solid sa mples; this advantage is a benefit in the analysis of complicated samples, especially for the direct analysis of solid samples.