UHPLC determination of catechins for the quality control of green tea

An ultra-high performance liquid chromatography (UHPLC) with UV detection method was developed forthe fast quantitation of the most represented and biologically important green tea catechins and caffeine.UHPLC system was equipped with C18 analytical column (50 mm × 2.1 mm, 1.8 um), utilizing a mobilephase composed of pH 2.5 triethanolamine phosphate buffer (0.1 M) and acetonitrile in a gradient elu-tion mode; under these conditions six major catechins and caffeine were separated in a 3 min run. Themethod was fully validated in terms of precision, detection and quantification limits, linearity, accuracy,and it was applied to the identification and quantification of catechins and caffeine present in green teainfusions. In particular, commercially available green tea leaves samples of different geographical origin(Sencha, Ceylon Green and Lung Ching) were used for infusion preparations (water at 85◦C for 15 min).The selectivity of the developed UHPLC method was confirmed by comparison with UHPLC–MS/MS anal-ysis. The recovery of the main six catechins and caffeine on the three analyzed commercial tea samplesranged from 94 to 108% (n = 3). Limits of detection (LOD) were comprised in the range 0.1–0.4 ug mL−1. Anorthogonal micellar electrokinetic (MEKC) method was applied for comparative purposes on selectivityand quantitative data. The combined use of the results obtained by the two techniques allowed for a fastconfirmation on quantitative characterization of commercial samples.