Mechanism of the Gas-Phase Hydrogen/Deuterium Exchange Associated with Positive Ion Direct Analysis in Real Time (DART)

Abstract

Gas-phase hydrogen/deuterium (H/D) exchange between D 2 O, CH 3 OD, CH 3 CH 2 OD, ND 3 and ascorbic acid was examined, in an attempt to understand the mechanism responsible for the gas-phase ion/molecular reactions that occur in Direct Analysis in Real Time (DART) ．Ionized water/ammonium clusters played an important role in the H/D exchange process, known as a transient microenvironment (TME) ．Argon was used as an alternative DART gas to eliminate formation of ionized water clusters. ese experiments clearly characterized the gas-phase H/D exchange process of positive-ion DART.