Aerosol Fluorescence Spectrum Analyzer for Rapid Measurement of Single Micrometer-Sized Airborne Biological Particles

摘要

We report the operation of an aerosol analyzer capable of measuring thefluorescence spectra of single micrometer-sized bioaerosol particles as they flow through the instrument. Particles entrained in an air stream initially traverse a cw (488-nm) trigger laser beam, where their elastic scattering and total fluorescence are measured with photomultipliers. When the elastic scattering and/or fluorescence signals exceed preset levels, a 266-nm UV probe laser is triggered to fire and illuminate preselected particles downstream from the trigger laser. The UV-laser-excited spectra of particles are measured with the instrument's image-intensified charge-coupled device (CCD) detector, which is gated to be on when the probe laser fires. We demonstrate the instrument's ability to capture the fluorescence spectra of single micrometer-sized airborne biological particles, including some simulants for biowarfare agents. Such spectra should be useful in differentiating between biological and nonbiological aerosols and in partially characterizing airborne biological particles.