Determination of adulterants in adulterant-fruit spirit blends using excitation-emission matrix fluorescence spectroscopy

Abstract

This study introduces a reliable method to detect adulteration of spirit drinks. Excitation-emission matrix (EEM) fluorescence in combination with parallel factor analysis (PARAFAC) and partial least squares (PLS) regression was used to determine the content of water and ethanol in adulterated fruit spirit samples. EEM fluorescence spectra recorded in the emission wavelength range of 315–450 nm and in the excitation wavelength range of 240–305 nm were used for PARAFAC. The model created using PARAFAC-PLS was able to predict the water and ethanol level in adulterated apple spirit with the root mean square error of prediction (RMSEP) values of 1.9 % and 1.8 %, respectively. Regarding adulterated plum spirit, the RMSEP values of 0.7 % and 3.5 % were obtained for water and ethanol, respectively. The aim of this work was to determine whether EEM-PARAFAC can be used to distinguish between plum and apple spirit. Better results were obtained for apple spirit and the method is useful also for water-apple spirit blends.