THERMOSPRAY-LC-MS ANALYSIS OF VARIOUS GROUPS OF POLYPHENOLS IN TEA .1. CATECHINS, FLAVONOL O-GLYCOSIDES AND FLAVONE C-GLYCOSIDES

This paper describes the application of thermospray-HPLC-MS (buffer io nization mode, single-stage MS, positive ion detection) to the analysi s of flavanols (catechins), flavonsl O-glycosides, flavone C-glycoside s as well as caffeine, theobromine, theogallin and theanine from tea. All compounds are detected as pseudo-molecular ions [M+H](+). Other mo lecular ion species are adducts with sodium, potassium, ammonium and s olvent clusters. The catechin gallates and the flavonol glycosides are fragmented. The fragmentation is temperature dependent. The glycoside bond is labile and consequently the flavonol glycosides have the prot onated aglycone as this base peak. The ester bonds in the catechin gal lates are more stable and the fragmentation is limited. The fragment p attern contributes to the structural information. LC-thermospray-MS is a good analytical tool for identifying the polyphenols mentioned abov e both in tea and other foodstuffs, especially in method development a nd structural elucidation.