LASER-INDUCED PLASMA ATOMIC EMISSION-SPECTROMETRY IN LIQUID AEROSOLS

Atomic emission spectrometry was performed in a laser-induced plasma in air. The plasma was produced by focusing the beam of an Ar-F (193 nm) excimer laser into a liquid aerosol nebulizer system. A liquid aerosol was generated with a concentric glass nebulizer-spray chamber assembly and carried into the plasma by the argon (0.5 l min-1) nebulizer gas. In general, the emission signal lasted ca. 35-40 mus after the laser pulse. The excitation temperature of the plasma decreased from 3994 K at 1 mus to 3607 K at 35 mus after the laser pulse. The solution limits of detection (3sigma of the blank) were determined for Na, Li, In, Al, Ga, Ca, Mg, K and Sr to be 0.9, 0.3, 10, 3, 3, 8, 3, 2 and 20 mug ml-1, respectively. The sensitivity obtained with this system is similar to that of a previous Nd:YAG wet droplet system reported in the literature.