The use of a dye laser for the detection of sub-picogram amounts of lead and iron by atomic fluorescence spectrometry

Abstract

The frequency-doubled radiation of a dye laser excited by the second harmonic radiation of a YAG:Nd 3+ laser has been used as light source in graphite-tube atomic fluorescence analysis. Detection limits and linear ranges of the analytical curves for two elements, Pb and Fe, were studied. Direct-line fluorescence at 373.5 mn for Fe and at 405.8 nm for Pb was observed. The limits of detection, obtained using linear extrapolation to the background level, were 25 pg/ml for Fe and 2.5 pg/ml for Pb. This corresponds to an absolute detection limit of 0.75 pg for Fe and 0.075 pg for Pb. In the case of Pb, saturation was reached at an intensity of the exciting radiation of about 20 kW/cm 2, but in the case of Fe, linearity was maintained up to 300 kW/cm 2.