Second-order advantage with excitation-emission fluorescence spectroscopy and a flow-through optosensing device. Simultaneous determination of thiabendazole and fuberidazole in the presence of uncalibrated interferences

摘要

This paper presents a novel approach for the simultaneous determination of two widely used fungicidesnin a very interfering environment, combining the advantage of a spectrofluorimetric optosensorncoupled to a flow-injection system and the selectivity of second-order chemometric algorithms.nThe sensor is based on the simultaneous retention of thiabendazole and fuberidazole on C18-bondednphase placed inside a flow-cell. After the arrival of the analytes to the sensing zone, the flow is stoppednand the excitation-emission fluorescence matrix is read in a fast-scanning spectrofluorimeter. Parallelnfactor analysis (PARAFAC) and unfolded and multidimensional partial least-squares coupled tonresidual bilinearization (U- and N-PLS/RBL) were selected for data processing. These algorithmsnachieve the second-order advantage, and are in principle able to overcome the problem of the presencenof unexpected interferences. The power of U-PLS/RBL to quantify both fungicides at parts-per-billionnlevels, even in the presence of high concentrations of spectral interferences such as carbaryl,ncarbendazim and 1-naphthylacetic acid, is demonstrated. Indeed, U-PLS/RBL allowed us to reachnselectivity using a commercial but non-selective sensing support. To the best of our knowledge, this isnthe first time the potentiality of the ‘second-order advantage’ is evaluated on a flow-injection system,nusing an unspecific supporting material and in the presence of three real interferences. Using a samplenvolume of 2 mL, detection limits of 4 ng mLu00021 and 0.3 ng mLu00021 for thiabendazole and fuberidazol werenrespectively obtained in samples without interferences. In samples containing interferences, the limits ofndetection were 17 and 1 ng mLu00021 for thiabendazole and fuberidazol, respectively. The samplenfrequency, including excitation/emission fluorescence matrix measurements, was 12 samples hu00021.nThe sensor was satisfactorily applied to the determination of both analytes in real water samples.