LC-MS/MS in glycomics and glycoproteomics analyses

Glycomic and glycoproteomic analyses include the characterization of oligosaccharides (glycans) conjugated to proteins. Glycan characterization is critical to obtain a comprehensive vision of the regulation and functions of glycoproteins of interest. Glycans are created through a complicated nontemplate-driven process by a set of competing enzymes that lengthen the embryonic chain. The complex nature of these structures, stemming from variable compositions and linkages, and the poor ionization efficiency make it challenging to characterize the oligosaccharides. However, there have been significant developments and progressive separation, in which mass spectrometry (MS) approaches have been at the center and have been the main reason for this development. The primary purpose of this chapter is to discuss and evaluate the current LC separation techniques conjugated with MS, with an emphasis on the isomeric resolution of glycans and glycopeptides.