Synchronous Detection of Laser-Induced Fluorescence

摘要

Many toxic or carcinogenic organic molecules have large absorption and fluorescence emission cross sections and can thus be detected by laser-induced fluorescence (LIF) in liquid samples at parts-per-billion levels or better. The technique of synchronous detection of laser-induced fluorescence (SDLIF) provides a way to distinguish between the fluorescence from a toxic molecule and the fluorescence from a background substance. This is done by synchronously scanning the laser excitation and fluorescence detection wavelengths at a fixed wavelength separation. What is measured in the overlap integral of the excitation and emission spectra that is considerably narrower than the entire fluorescence spectrum. The discussion of these techniques is centered on the point and remote detection of polynuclear aromatic hydrocarbons, aromatic amines, and organophosphates having applications in certain manufacturing processes as well as in coal liquefaction and gasification plants. (ERA citation 07:057555)