HPLC-MS/MS profiling of proanthocyanidins in teas: A comparative study

► Method to profile proanthocyanidins (PA) in crude plant extracts by LC-MS/MS. ► Mass spectral fragmentation patterns enable classification of type and size of PAs. ► Reports for the first time the detection of PA tetramers in black tea. ► Reports for the first time the detection of PA trimers and tetramers in oolong tea.