Mass spectrometry (MS) is a powerful measurement tool to provide both quantitative and qualitative information of analytes at the molecular level. We are interested to push the limit of MS to achieve some “odd” capabilities. One research focus is to use MS to provide mechanistic insight of radical-biomolecule interactions, which are highly relevant to aging, health, and diseases. We have taken a unique approach to address this issue by studying gas-phase ion/radical reactions. Instrumentation and methods have been developed to enable ion/radical reactions in an electrospray ionization plume or inside a linear ion trap mass spectrometer. These new methods have allowed us to synthesize and characterize the chemical properties of bio-radicals such as peptide sulfinyl radical (R-SO•), thiyl radical (R-S•), and perthiyl radical (R-SS•). Analytical applications based on ion/radical reactions are developed to enhance disulfide peptide sequencing as well as double bond location determination in lipids. Another focus of our research is to develop MS methods to assign stereo-chemical information of oligosaccharides. With the combination of “retro-analysis” methodology and multiple stage tandem mass spectrometry (MSn, n>2), we can achieve confident determination of stereo-structures (sugar identity and anomeric configuration) of individual sugar units within linear oligosaccharides.
Prof. Facundo Fernandez (404-385-4432).