Hydrogen/deuterium exchange using a coaxial sheath-flow interface for capillary electrophoresis/mass spectrometry

The interfacing of capillary electrophoresis (CE) with mass spectrometry (M S) is well established and may be accomplished by use of either a coaxial a rrangement or by employing a liquid T-junction. In both these interfaces a make-up flow is introduced. This is required because of the mismatch in how rates for capillary electrophoresis similar to nL/min and 'true' electrosp ray similar to 2-10 mu L/min. Electrical connectivity may also be establish ed where the liquid flows meet (the introduction of nanospray renders the u se of make-up flow unnecessary). Hydrogen/deuterium (H/D) exchange occurs in solution when there are labile hydrogen atoms present in a molecule. The establishment of the presence and the number of such exchangeable hydrogen atoms may be of importance in the identification and differentiation of compounds. It may also be an aid in the structural elucidation of unknown materials. We have investigated the f easibility of carrying out H/D exchange via a CE/MS interface. This involve d the addition of D2O to the sheath flow and our preliminary results showin g the separations of drug substances, subsequently undergoing exchange, are presented. Copyright (C) 2000 John Wiley & Sons, Ltd.