Trace determination of carbendazim, fuberidazole and thiabendazole in water by application of multivariate calibration to cross-sections of three-dimensional excitation-emission matrix fluorescence

The simultaneous determination of carbendazim, fuberidazole and thiabendazo le was accomplished by cross-section (CS) fluorimetry in combination with m ultivariate calibration algorithms. The total luminescence information of t he compounds was used to optimise the linear trajectories of the CS. A comp arison between principal component regression (PCR) and two partial least s quares (PLS) algorithms, PLS-1 and PLS-2, with different pre-processing met hodologies was made. The final model, which applied the PLS-1 method, built using pesticide standard and emission spectra, was successfully used for t he determination of these compounds in synthetic mixtures. However, a diffe rent PLS-1 multivariate calibration model, based on CS through the total lu minescence spectroscopic data, was necessary for determining the cited pest icides in water samples. Mean centring was the best pre-processing techniqu e in both PLS-1 models. This later calibration model was built from ultra-p ure water samples spiked with known carbendazim, fuberidazole and thiabenda zole concentrations, after solid-phase extraction (SPE). The method, which had a precision better than 5%, was shown to be suitable for carbendazim, f uberidazole and thiabendazole monitoring in water samples at trace levels.