In this work, I coupled liquid-phase separations to mass spectrometry to analyze peptides, oligosaccharides, and intact antibodies. I first investigate the proteome of wing imaginal discs of Drosophila melanogaster larvae incubated in adult Drosophila melanogaster extract. Nanoflow reverse-phase separations were coupled to mass spectrometry for identification of both the wing disc proteome and the incubation matrix proteome. I next coupled capillary electrophoresis to mass spectrometry for the analysis of standard oligosaccharide solutions and glycosylation modifications cleaved from human IgG. I then developed a novel glycan labeling technique utilizing rhodamine 6G. Finally, capillary isoelectric focusing coupled to ESI-TOF-MS is used for the online focusing, separation, and identification of monoclonal antibody charge state variants.