KINETICS OF RELEASE OF CARBON AND CARBON-MONOXIDE FROM A GRAPHITE-FURNACE INVESTIGATED BY ELECTROTHERMAL VAPORIZATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

Detection of carbon-containing molecules released during the high temperature heating of a dry, unloaded HGA-type graphite furnace (GF) has been undertaken by interfacing the GF to an ICP-MS. Desorption of O-2 (as CO) chemisorbed onto the GF surface can be discriminated from that produced as a result of continuous oxidation of the surface by gaseous O-2 impurity. Because plasma-induced dissociation of CO is negligible, signals arising from C do not have to be deconvoluted from those of CO. To a first approximation, the formation of C and CO can be treated as independent processes. A theoretical analysis of the transient experimental signals is presented.