Screening method for identification of adulterate and fake tequilas by using UV-VIS spectroscopy and chemometrics

Based on UV-VIS spectroscopy and chemometric techniques a screening method is presented with which the studied brands of white and rested tequila can be differentiated among them and on the other hand adulterate and fake tequilas can be distinguished from the corresponding genuine brands Eighty bottles of tequila (39 white type and 41 rested type) were studied and purchased at liquor stores special care was taken to get different batches Through the use of support vector machine (SVM) principal component analysis (PCA) and linear discriminant analysis (LDA) the studied tequilas were differentiated and classified Into 8 sets 4 sets of white and 4 of rested tequilas each set corresponded to a specific tequila brand Seven additional samples with similar labeling than the 80 samples were used to validate the method and it was found that each sample was located within the ellipse of confidence of the corresponding tequila brand Furthermore 14 adulterated samples were generated from 2 bottles of tequila one white and one rested and they could be distinguishable from the genuine tequila i e they were outside of the corresponding ellipse of confidence In addition the screening method here presented was employed to analyze rested tequilas that were purchased on the street market i e fake tequilas with the same label than 3 of the used brands in this work These samples were discriminated from the corresponding genuine tequila brand The results suggested that the reported method could play an important role when a quick trustworthy and feasible result on site is needed since the test of the spirit takes minutes affording robustness reliability and in addition a skilled worker is not required necessarily to apply the method (C) 2010 Elsevier Ltd All rights reserved