A systematic approach to analyzing catechins and catechin derivatives in Ceylon black tea using liquid chromatography coupled with triple quadrupole mass spectrometry.

The structural complexity and limited standards for catechin derivatives in black tea present significant analytical challenges in tea research. This study aimed to develop a systematic approach to extract and analyze catechins and derivatives in Ceylon black tea from four Sri Lankan regions (Dimbula, Nuwara Eliya, Uva, Ruhuna) using optimized extraction conditions, LC-QQQ/MS, and antioxidant assays. A design of experiment (DoE) optimized solvent (0-100 % acetone-water), temperature (30-60 °C), and time (0-150 min), identifying 49.8 % acetone, 123.6 min with sonication, and 49.8 °C as optimal (desirability 0.743). Twelve catechin-related compounds were identified by LC-QQQ/MS, including theaflavins and tentatively annotated derivatives. TPC, TFC, DPPH, and ABTS assays showed Nuwara Eliya tea had the highest antioxidant capacity, linked to elevated polyphenols and flavonoids. This workflow offers a robust framework for studying catechin derivatives with limited standards, offering a practical solution for black tea research and quality assessment.