INVESTIGATION OF TRANSIENT MOLECULAR ABSORPTION IN A GRAPHITE-FURNACE BY LASER-INDUCED PLASMAS

The transient molecular species that are produced in electrothermal atomizers are probed by backlighting the furnace with continuum emission from laser-induced plasmas. Laser plasmas provide a stable and strong continuum spectrum in the UV region for molecular absorption studies. These plasma sources exhibit a substantial improvement in UV absorption measurement over the more conventional sources, permitting good time resolution. The molecular absorption spectrum from 190 to 320 nm for NaI, NaCI, and KH2PO4 are illustrated. The temporal and spectral resolution of this instrument are 100 ms and 0.2 nm, respectively.