Development and validation of a High Performance Liquid Chromatography-Diode Array Detection method for the determination of aging markers in tequila

A solid-phase extraction procedure followed by analysis by high performance liquid chromatography (HPLC) with UV–vis photodiode array detection (DAD) is proposed to simultaneously determine 11 aging markers in tequila. The method showed good intraday (n = 5) and interday (n = 3) precision, RSD < 1.6% in both cases, for each of the identified compounds. The calibration curves were linear at the tested ranges (R2 > 0.999). Good recoveries (84.2–108.5%) were obtained for 10 of the 11 compounds studied; and the LOD and LOQ ranged from 0.62 to 4.09 μg/mL and 1.9–12.4 μg/mL, respectively. The proposed methodology was applied to a set of 15 authentic tequila samples grouped by aging state (blanco, reposado and añejo). An ANOVA analysis combined with discriminant analysis with stepwise backward variable selection was used to differentiate between the various aging groups based on their oak related compounds content.