Concurrent Analysis of Theanine, Caffeine, and Catechins Using Hydrophobic Selective C₁₂ Stationary Phase

Abstract

A fast reverse phase-high performance liquid chromatography-diode array detector (RP-HPLC-DAD) method has been developed and validated for simultaneous analysis of major bioactive constituents of tea. The collective separation of theanine, caffeine, and catechins has been achieved by using a new hydrophobic selective C₁₂ stationary phase. The separation was done without any pre-column derivatization and using simple gradient solvent system of acetonitrile and water containing 0.01% TFA. We have achieved rapid separation of all these components within 16 min with very good peak resolution and sensitivity. The method also exhibits very good linearity with correlation coefficients between 0.9918 and 0.9999 for all the compounds. A comparative assessment study for the estimation of above-mentioned phytoconstituents from different solvent extracts as well as brewed infusions of green and black teas was also performed using this liquid chromatography (LC) method. The results of the comparative evaluation studies have showed that green tea extracts and brewed green tea infusions contain high yield of these phytoconstituents in comparison to black teas. The present HPLC method is quite applicable for biochemical analysis of wide range of tea samples including various types of teas, tea extracts, tea infusions, instant teas, ready-to-drinks (RTDs), and various other tea based value added food products and nutraceuticals and beverages.

Keywords:

• caffeine
• catechins
• DAD
• RP-HPLC
• tea
• theanine

Acknowledgments

The authors are very thankful to Director CSIR-IHBT for encouragement. Reviewers are also acknowledged for valuable comments and suggestions.

Additional information

Notes on contributors

Harsh Pratap Singh

Harsh Pratap Singh is now Scientist Emeritus of the CSIR-Institute of Himalayan Bioresource Technology.