Variable-angle synchronous fluorescence spectrometry and rank annihilation methods for mixture resolution.

The potential of variable angle synchronous spectroscopy (VASS) for fluorescent mixtures resolution was assessed and compared with the rank annihilation method (RAM). For this purpose, a set of excitation-emission matrices from three standard cyclodextrin fluorescence-enhanced solutions of the pesticides aminocarb, carbendazim and coumatetralyl and a mixture of them was obtained. Careful selection of the spectral routes to be scanned provides analyte signals that are free of interferences. Application of the rank annihilation method to excitation-emission matrices (EEMs) obtained by conventional scanning spectrofluorimetry gives quantitative results that show poor precision and accuracy when compared to those of VASS. The recoveries from ternary mixtures by VASS are within 99-104% and by RAM within 84-130%.