Zeolite Slurry Analysis Using Freon-Assisted Graphite Furnace Vaporization for Inductively Coupled Plasma Atomic Emission Spectrometry

Abstract

Halogen-assisted electrothermal vaporization (ETV) was used as a sample introduction mechanism for inductively coupled plasma atomic emission spectrometry. Freon-12™ was used as a gas-phase halogenation reagent in the ETV graphite furnace to enhance vaporization of carbide-forming elements by converting them into metal halides. With Freon ETV, detection levels for Zn, Pb, Cd, Mn, V, Cu, Ti, and Ca were lower than those obtained with conventional nebulization of liquid standards. A zeolite sample was analyzed for the refractory elements chromium and vanadium. Without Freon, the signals for these elements were very low; however, with Freon, the signals were dramatically improved. Detection limits of 1.4 μg/g and 0.3 μg/g, respectively, were obtained for these elements. A sheathing and cooling gas flow was introduced to reduce analyte vapor condensation on tubing walls and to promote aggregate formation. This additional flow enhanced the quality of signal with the zeolite but proved to be detrimental for the determination of refractory elements in liquid standards with or without halogenation. The precision of determination for the zeolite sample varied from 3% for cadmium, to 6% for lead.