Characterization of organic dyes aided by hydrogen-deuterium exchange in liquid secondary ion mass spectrometry (liquid SIMS)

Abstract

Isotope exchange methods in organic mass spectrometry serve as powerful tools to elucidate the structure of complex molecules. We have used hydrogen-deuterium exchange in liquid SIMS to characterize non-volatile organic dyes, both to corroborate and to elucidate dye structures. Presented here are SIMS spectra of several cationic dyestuffs dissolved in glycerol and perdeuteroglycerol (glycerol-D8) liquid matrices. Dyes that contain so-called active hydrogens exhibited mass shifts in the spectra obtained from labeled and unlabeled glycerol, allowing inferences about molecular structure to be made. The exchange methodology is shown to be useful in the study of reductive processes occurring in the liquid matrix and in distinguishing isomeric forms of dye compounds.