Abstract: An online ultra-high performance liquid chromatography photo-diode array-mass spectrometry-2,2’-amino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) di-ammonium salt (UPLC-PDA-MS-ABTS) cation radical method was established to identify the antioxidant components in vine tea. Trolox was used as the reference substance and the standard curve method was used to quantitatively analyze the antioxidant activity of dihydromyricetin as the major bioactive constituent in vine tea. Four compounds were identified from vine tea, including dihydromyricetin (DMY), which was the main antioxidant compound of vine tea. The antioxidant activities of 12 batches of commercially available vine tea samples were analyzed. Results showed that the samples produced in Enshi of Hubei province and those produced in Wuyishan of Fujian province had the highest antioxidant activity. The developed quantitative method is fast, stable and reliable for the online assay of the antioxidant activity of vine tea.

Key words: vine tea; ultra-high performance liquid chromatography photo-diode array-mass spectrometry-2,2’-amino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) di-ammonium salt cation radical; antioxidant activity; identification; quantitative analysis