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The effect of Pd on analyte absorbance signals was evaluated for several elements including As, Cd, Cr, Pb, Sn and TI. Conventional furnace operating procedures and wall atomisation were used. The Pd reduction step was found t o be essential for the recovery of Pb and TI when a halide matrix was present. Absorbance profiles were found to be sensitive to the mass of Pd present. Slight positive shifts in the peak temperature were noted for low (ng) levels of Pd, while higher levels of Pd caused increasing shifts in the peaktemperature. Excluding Pb, the peak-area absorbances increased with Pd mass while peak-height absorbances generally reached a maximum at Pd masses below 2 pg. The data imply that the mass amount of the Pd chemical modifier should be considered during the development of analytical methods which include Pd.

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A low-pressure graphite furnace atomic absorption spectrometry technique Is presented which, for aqueous Pb samples at 0.15 Torr, results In a 2 orders of magnitude reduction In sensitivity and a working range that extends to about 1 pg. The limit of detection Is 5 ng of Pb. Sticking Is diminished for refractory analytes (e.g., V), thus reducing memory effects and peak tailing. Solid sample analysis Is demonstrated for Pb In a phosphorlzed Cu alloy, for which low-pressure atomization minimizes Cu vaporization while allowing for quantitative determination of Pb when compared to a calibration curve prepared from aqueous standards. In addition, the appearance of multiple peaks suggests the use of the technique for differentiating between various forms or locations of Pb within the sample. This Is In contrast to atmospheric vaporization where only one broad peak Is observed.

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