Identification and quantification of furanic compounds in tequila and mezcal using spectroscopy and chemometric methods

In this paper, two Mexican white spirits with appellationd'origen contrôlée (AOC), i.e., tequila and mezcal were easily discriminated by using UV-Vis spectrophotometry and chemometric techniques. The spectra were recorded in the range of 250-400 nm and their main feature is a broad band centered about 280 nm whose amplitude changes according to the type of beverage and brand, however, additional differences are pointed out through multivariate analysis that makes a fair differentiation between the beverages. By using RP-HPLC with UV detector, the compounds that originate the absorption band were determined. Thus, the spectrum of each beverage in the wavelength range of 250-330 nm, approximately, is a particular mixture of furfural (FUR), 2-acetylfuran (2AF) and 5-methylfurfural (5MF). Further, the absorption spectra of mixtures of FUR, 2AF and 5MF standards were recorded at several concentrations and by using a partial least square model (PLS), the concentrations of those compounds were predicted in test and spirit samples. When these results were compared to those obtained by HPLC, the correlation coefficients were R > 0.920. Therefore, with this methodology one builds up an alternative method to identify and quantify some furanic compounds in white tequilas and mezcals. In addition to these results, the methodology can be performed on site and results about specific quality controls can be obtained within minutes.