Reactive collisions in quadrupole cells. 2. H/D exchange reactions of enolate ions with CH3od and C 2H 5OD.

The H / D exchange reactions of enolate ions with CH3OD and C2H5OD at low collision energies in the quadrupole collision cell of a hybrid tandem BEqQ mass spectrometer have been studied. The optimum parameters for exchange were elucidated using the enolate ion of acetone as a test reactant ion. With the exception of the enolate ions of 2, 4-pentanedione and dimethylmalonate, all the enolate ions studied underwent exchange with CH3OD and C2H5OD. Ion signals were observed corresponding to exchange of from one to all of the enolic hydrogen atoms. The H / D exchange reaction was more facile with C2H5OD as the reagent gas, and the results with this gas clearly permit a count of the number of enolic hydrogen atoms present in the molecule.