Laser induced fluorescence and electrothermal atomization: how far from the intrinsic limit of detection?

Abstract

A comparison is given between the experimental detection limits obtained for lead and thallium atoms by the technique of laser induced fluorescence with electrothermal atomization and those calculated under the assumption that the limiting noise is due to the intrinsic error in the signal itself (intrinsic detection limit). Four pulsed, tunable dye laser systems are considered, in which the dye is pumped by an excimer laser, a Nd-YAG laser, a N 2 laser and a Cu-vapor laser. The fluorescence is excited and observed longitudinally in a graphite tube atomizer. It is shown that the detection limits obtained are greater than the calculated intrinsic ones by a factor ranging from 79 to 1.3 × 10 4, depending upon the laser system. Under ideal experimental conditions, i.e. if the detector noise limit is achieved, the intrinsic detection limit for lead in the case of Nd-YAG and N 2-pumped dye laser systems is practically reached.