LASER-EXCITED SYNCHRONOUS LUMINESCENCE SPECTROSCOPY

The use of lasers as excitation sources for molecular luminescence oft en results in improvements in sensitivity and limits of detection (LOD s). Synchronous luminescence (SL) spectroscopy, in which both excitati on and emission wavelengths are scanned simultaneously, provides a con venient means to improve selectivity (often dramatically) in the analy sis of multicomponent mixtures using room-temperature luminescence. We report here on the first use of a dye laser as an excitation source f or SL at room temperature. The performance of the laser synchronous lu minescence (LSL) system is described for the analysis of four polyarom atic compounds, for one of these-tetracene-the LOD was 680 zeptomoles (10(-21) mol) in the volume probed by the laser. In addition to impres sive sensitivity and selectivity, the laser system used is quite small and can be considered as an attractive source for portable SL instrum ents designed for in-field screening of environmental samples.