FLUORINATION WITH POLYTETRAFLUOROETHYLENE SLURRY IN ELECTROTHERMAL VAPORIZATION-INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

A method was developed to determine refractory elements by inductively coupled plasma-atomic emission spectrometry (ICP-AES) with sample int roduction by electrothermal vaporization (ETV). A slurry of polytetraf luoroethylene (PTFE) was used as fluorinating reagent to promote the v aporization of refractory elements from a graphite furnace and to avoi d the formation of difficult volatile carbides. With this treatment th e refractory elements can be efficiently vaporized, and subsequently i ntroduced into the plasma. The detection limits of this method were in the picogram to sub-nanogram range and superior to those obtained wit h conventional nebulization systems, and were comparable with those ob tained with similar ETV-ICP-AES techniques. The analyte vaporization a nd transport process was systematically explored, and the correspondin g vaporization and transport mechanisms of refractory elements in this system have been proposed. The matrix effects and sample particle siz e effects in fluorination assisted ETV-ICP-AES were significantly redu ced. Therefore, an effective method for lowering the matrix interferen ces has been proposed.