Performance of an automated gas chromatograph-silica furnace-atomic absorption spectrometer for the determination of alkyllead compounds

An automated gas chromatograph-atomic absorption spectrometer was used to study the decomposition-atomization process for alkyllead compounds in a heated quartz tube. Longer term stability of the system was achieved with a purging cycle in which the quartz furnace was flushed with large air flows during solvent elution prior to returning to normal reducing atmospheres in hydrogen. The system response was optimized by using univariate procedures; it was insensitive to changes in atomizer surface temperatures above 800/sup 0/C. No changes in atomization efficiency for quantities of lead between 30 pg and 30 ng were observed, suggesting that excess lead scavenger was present. Although less efficient than hydrogen, other gases also supported the decomposition-atomization of the analytes. A major portion of the lead not atomized in air or nitrogen was deposited on the surface of the quartz walls and was revolatilized and atomized extremely rapidly if hydrogen was admitted to the furnace. Hydrogen radicals are postulated to mediate both the revolatilization and atomization steps. 23 references, 7 figures, 1 table.