OPTICAL-EMISSION SPECTROSCOPY STUDIES OF THE INFLUENCE OF LASER-ABLATED MASS ON DRY INDUCTIVELY-COUPLED PLASMA CONDITIONS

The amount of ablated mass can influence the temperature and excitatio n characteristics of the inductively coupled plasma (ICP) and must be taken into account to ensure accurate chemical analysis. The ICP elect ron number density was investigated by using measurements of the Mg io nic to atomic resonant-line ratios during laser ablation of an aluminu m matrix. The ICP excitation temperature was measured by using selecte d Fe lines during laser ablation of an iron matrix. A Nd:YAG laser (3 ns pulse duration) at 266 nm was used for these ablation-sampling stud ies. Laser energy, power density, and repetition rate were varied in o rder to change the quantity of ablated mass into the ICP. Over the ran ge of laser operating conditions studied herein, the ICP was not signi ficantly influenced by the quantity of solid sample. Therefore, analyt ical measurements can be performed accurately and fundamental studies of laser ablation processes (such as ablation mass roll-off, fractiona l vaporization) can be investigated using inductively coupled plasma-a tomic emission spectroscopy (ICP-AES). (C) 1998 Elsevier Science B.V.