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 introduction by electrothermal vaporization (ETV). A slurry of polytetrafluoroethylene (PTFE) was used as fluorinating reagent to promote the vaporization of refractory elements from a graphite furnace and to avoid the formation of difficult volatile carbides. With this treatment the refractory elements can be efficiently vaporized, and subsequently introduced into the plasma. The detection limits of this method were in the picogram to sub-nanogram range and superior to those obtained with conventional nebulization systems, and were comparable with those obtained with similar ETV-ICP-AES techniques. The analyte vaporization and transport process was systematically explored, and the corresponding vaporization and transport mechanisms of refractory elements in this system have been proposed. The matrix effects and sample particle size effects in fluorination assisted ETV-ICP-AES were significantly reduced. Therefore, an effective method for lowering the matrix interferences has been proposed.