The analysis of polyphenols in tea

The analysis of polyphenols in tea extracts is important due to their potential health benefits. Therefore,
efficient and high throughput analytical methods have been developed for the separation of seven
predominant polyphenols, also known as catechin derivatives, present in tea extracts. Columns packed
with sub-2-mparticles operating at elevated pressure (UHPLC strategy) were selected to improve chromatographic
performance. The potential of UHPLC–UV was demonstrated with baseline resolution of all
standard catechins in only 30 s using a 50-mm column packed with 1.7-mparticles. When dealing with
real samples such as tea extracts, however, longer columns of up to 150mm in length were employed
to enhance the separation of catechin derivatives and other constituents within the tea samples while
maintaining an acceptable analysis time. Two strategies based on 2-D experiments were proposed to
clearly identify catechins. Firstly, a liquid–liquid extraction procedure was added prior to the UHPLC–UV
analysis to decrease the complexity of the sample. Secondly, UHPLC was coupled to ESI-MS/MS to attain
sufficient sensitivity and selectivity between catechin derivatives and other constituents of tea extract.
These two strategies were found extremely promising as a clear discrimination of catechins from the
matrix could be attained.