Excitation-emission matrix fluorescence based determination of carbamate pesticides and polycyclic aromatic hydrocarbons

The ability to accurately quantitate trace pesticides and polycyclic aromatic hydrocarbons (PAHs) by excitation-emission matrix (EEM) fluorescence spectroscopy, when coupled with parallel factor analysis (PARAFAC) deconvolution of the EEM spectra, is demonstrated and discussed. Two EEM fluorometers were investigated. One fluorometer, using a cuvette cell sample holder, realized limits of detection of 1.1, 6.6, and 13 ppb for I-naphthol, carbaryl, and carbofuran in methanol mixtures, respectively. 0.2 ppb limits of detection were also observed for three PAHs. With this fluorometer, the PARAFAC model was employed to resolve the analyte spectra from overlapping fluorescence signals and Raman scattering profiles. Employing a second fluorometer with a fiber-optic probe for remote sampling yielded 10-30 ppb limits of detection for 9 PAHs. The PARAFAC model was required here to resolve the PAH spectra from the instrumental background. (C) 1999 Elsevier Science B.V. All rights reserved.