RAPID IDENTIFICATION OF ORGANIC CONTAMINANTS IN PRETREATED WASTE WATER USING AOTF NEAR-IR SPECTROMETRY

摘要

A near-infrared analyzer utilizing state-of-the-art acousto-optic tunable filter (AOTF) spectrometry with digital wavelength control and a high D~(*) extended-range InGaAs TE-cooled detector provides excellent wavelength repeatability (better than 0.02 nm) and very high signal-to-noise ratio. Because the AOTF dispersive element is completely solid-state (no-moving parts), as is the entire spectrometer, the instrument is small, rugged and very reliable. Using this spectrometer, methods employing chemometrics have been developed and applied to measure organic contaminants such as gasoline and a variety of jet fuels in water. Qualitative identification of contaminants was achieved with discriminant analysis software developed specifically for this task. Both the technique of grouping sample spectra into specific clusters based of Mahalanobis distances and that of matching each spectrum with the most representative member of the appropriate group of calibration spectra were used to identify contaminants. After initial classification, appropriate qualitative chemometric calibrations may be applied to more accurately assess the level of contamination. This instrument will be used to evaluate ground water supplies.