IM-MS/MS as alternative method for existing n-UPLC separations of isomers and closely related compounds

摘要

Previously: development nUPLC-IM-MS-MS(MS) method: determine drift times from complex mixtures. Experiment 1: observation multiple t_D's for melphalan (m/z 305); related compounds show only single t_D. 1. CID at different stages of MS: Transfer CID is preferred since t_D's of precursor ("conformer") are retained; both "conformers" have unique CID pattern (m/z 168 fragment). 2. Computational calculations help to understand presence of multiple t_D's; further processing of data and comparison to experimental CCS necessary. Experiment 2: separation of isomers of small molecules; small but significant t_d shift for melphalan's m/z 537dimer isomers (O and Δ). 1. Similar separations for isomers of other classes of compounds (data not shown). 2. Further optimization: different (CO_2, Ar) mobility gases. In conclusion: melphalan as model to illustrate possibilities of IM-MS mass spectrometer. 1. Methods described by us: applicable in wide field of pharmaceutical LC-MS analyses, saving time and resources.