COLD-PLATE SAMPLING OF INTERNAL-COMBUSTION AEROSOLS FOR DIRECT LASER-INDUCED FLUORESCENCE ANALYSIS

Contaminated aerosols, produced by internal combustion processes, are of considerable environmental concern. Laser Induced Fluorescence (LIF ) was applied for fast analysis of such aerosols. A ''cold-plate type' ' sampler, held at several fixed temperatures, was used for the in-sit u, rapid pre-concentration of them. This way, the ambient air moisture vapors quickly condense into microscopic size water droplets. These, in turn, become polluted by the incoming nux of aerosols that, while b eing captured within, undergo accumulation (dissolve or suspend). Comp arative sensitivity of LIF spectra to application of a non-polar solve nt (hexane) to these contaminated aqueous samples is addressed. Insitu obtained LIF spectra allow non-destructive characterization of vehicl e engine performance.