Calibration method
For the determination of calibration curves, standards of (+)-
catechin, (−)-epicatechin, (−)-epigallocatechin, (−)-epicate-
chin gallate, (−)-epigallocatechin gallate were prepared in
70/30 methanol/water (v/v)at concentrations comprised be-
tween 0.3 mg/mL and 2 mg/mL. Dosages of catechins were
performed using the selected ion monitoring (SIM) mode to
increase sensitivity compared to the full scan mode.