The coupling of a high-performance liquid chromatograph with a sensitive and selective laser-excited atomic fluorescence spectrometry (LEAFS) detector is described. In connection with this, a study of the signal and noise characteristics of instrumentation for dispersive, nondispersive, and front surface LEAFS is reported together with a comparison of the sensitivity and selectivity achieved with high-performance liquid chromatography (HPLC)-flame LEAFS, HPLC-ultraviolet (UV), and HPLC-continuum source excited flame atomic fluorescence spectrometry (AFC) instrumentation. The HPLC-flame LEAFS instrumentation was applied to an investigation of the Mn species responsible for (methylcyclopentadienyl)manganese tricarbonyl (MMT) toxicity in rats. The detection limits for various organomanganese species by HPLC-flame LEAFS ranged from 8 to 22 pg of manganese. Recovery of these compounds from rat urine varied between 80% and 100%, with a reproducibility of between 4% and 8% relative standard deviation. Preliminary data for the HPLC-flame LEAFS determination of toxic alkyltin compounds are reported.
Air, drawn by vacuum through a jet, was impacted against the inside surface of an atomic absorption graphite electrothermal atomizer (ETA). The amounts of the particles thus collected were determined at the ng m-3 level by graphite furnace atomic absorption or at the pg m-3 level by laser excited atomic fluorescence. The overall reproducibility of two sets of measurements, made 7 months apart, was 23%, with no significant difference between the two sets of data, based on Student's "t" test at the 95% confidence level. Short-term reproducibility varied from 13% to 34% depending upon the air concentration of the metal. The method shows promise for monitoring long-term effectiveness of the filtering systems in trace metal clean rooms. It was not possible to test for accuracy, due to the low concentrations involved, but accuracy was expected to be within a factor of 2 or 3 of the actual value, based on theoretical aspects of impaction.
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