Combination of laser-induced fluorescence and diffuse-reflectance spectroscopy for the in situ analysis of Diesel-fuel-contaminated soils

Results of our laser-induced fluorescence (LIF) and diffuse-reflectance inv estigations of quartz sand and different soils spiked with Diesel fuel are reported. The LIF calibration functions, which were found to be significant ly different for the various matrices, and the limits of detection were det ermined. For excitation at lambda(ex) = 266 nm, the Limits of detection obt ained ranged from 7 parts in 10(6) for quartz sand to similar to 200 parts in 10(6) for dark sand with organic matter and for dark pest. Furthermore, the diffuse-reflectance spectra of the matrices in the ultraviolet-near-IR range were determined. An attempt to correlate the slopes of the LIF calibr ation functions with the reflectances of the matrices is presented. The obt ained normalized calibration functions are well suited to take into account relevant optical soil parameters and to reduce the variability of the LIF calibration behavior significantly. (C) 1999 Optical Society of America.