ANYL 292 |
| Although tea catechins are the focus of increasing research interest due to their association with disease prevention, their chemical analysis remains difficult because catechins exist naturally as stereoisomers. We have investigated the use of gas-phase hydrogen/deuterium (H/D) exchange reactions in a quadrupole ion trap mass spectrometer to differentiate between four pairs of tea catechin stereoisomers. Using deuterium oxide as the exchange reagent, we have observed differences in the extent of deuterium incorporation and the H/D exchange rates for the galloylated catechin stereoisomers studied. In contrast, we have determined that the non-galloylated catechin isomers are indistinguishable by their H/D exchange kinetics over a wide range of reaction times. Interestingly, the non-galloylated catechins undergo H/D exchange to a greater extent than the galloylated species, incorporating deuterium at aromatic ring and active phenolic sites. We have correlated our results with molecular models that elucidate subtle structural variations in the catechin stereoisomers that lead to their differing H/D exchange kinetics.
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Analytical Approaches: Mass Spectrometry
1:30 PM-4:20 PM, Wednesday, 13 September 2006 Moscone Center -- Room 124, Oral
Division of Analytical Chemistry |