( ch harder to achieve via conventional a...)Screening and classifying hazardous waste samples

Experimental Procedures
Computerized search routines for classifying spectra based on feature sets and similarity measures were developed. For fluorescence, pattern recognition factors encompassed spectral area, peak positions, and angular distance between spectra.

For all fluorescence spectra, The FLUOROLOG research spectrofluorometer system included a single-grating excitation monochromator and a double-grating emission monochromator. The excitation source was a 150-W xenon lamp. Both emission and reference detectors contained photomultiplier tubes.

Twenty-nine reference oil samples were obtained from the Environmental Protection Agency and the U.S. Coast Guard Research and Development Center. These references were chosen to be representative of the principal types of petroleum oils: light fuels, heavy fuels, and crude oils. Standard solutions were prepared from the reference oils at a concentration of 20 g/g in cyclohexene. Reference solutions for polychlorinated biphenyl (PCB) analysis were prepared by dilution to concentrations of 1030 g/g in cyclohexene. Real-world samples obtained for analysis were divided into three groups: contaminated soil samples, neat samples that appeared to be pure oils, and liquid samples (many of which contained a water phase) that were not pure oils.

All spectra presented herein were taken with the excitation bandpass at 4.5 nm, and emission band-pass at 0.9 nm. Excitation was at 254 nm.

Results and Discussion
The 29 reference oils were characterized by their emission spectra as well as by data obtained from synchronous scanning. Eastwood and Lidberg tabulated all of this information, categorizing the results of their experiments according to spectral features like maximum peak wavelengt
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