Mitigation of Rayleigh and Raman spectral interferences in multiway calibration of excitation-emission matrix fluorescence spectra

A weighted parallel factor analysis (W-PARAFAC) model is applied to excitat ion-emission matrix (EEM) fluorescence spectra of carbamate pesticides to a id with calibration in the presence of Raman scattering. Traditional PARAFA C inefficiently models the Raman scattering, resulting in prediction and ca libration errors when a significant background is present. Four different w eighting strategies were investigated and compared with subtraction of the appropriate sample background. Using a binary weighting strategy produced s uperior results, compared with a continuous distribution of weights. Furthe r choice of weighting strategies, which are optimized to include either max imum analyte signal or to exclude a maximum amount of background scattering , is dependent on the degree of overlap and relative signal intensity.