Screening method for identification of adulterate and fake tequilas by using UV–VIS spectroscopy and chemometrics (original) (raw)

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Adulterated and fake tequila UV–VIS spectroscopy 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.