Mobility labeling for parallel CID of ion mixtures

An ion mobility/mass spectrometry technique has been developed to record co llision-induced dissociation patterns for multiple ions in a parallel fashi on. In this approach, a mixture of ions is separated in a drift tube on the basis of differences in mobilities through a buffer gas. As the ions exit the drift tube, they are accelerated into a collision cell and the ensuing fragment ions are dispersed by differences in mass-to-charge (m/z) ratios i n a time-of-flight mass spectrometer. Fragment ions that are formed in the collision cell have drift times that are coincident with their antecedent p arent ions, allowing the origin of all fragments formed from the mixture of ions to be determined. The approach is demonstrated by examining fragmenta tion patterns of the [M + H](+) parent and a series of a-, b-, and y-type f ragments of [D-Ala(2,3)]methionine enkephalin.