>These studies focus on developing mass spectral-based measurement protocols, reference data, and reference materials for classes of glycans, glycopeptides, and glycoproteins relevant to protein therapeutics. This requires the development of measurement methods and data analysis techniques that enable the characterization of these materials at the molecular level to enable reliable, physically-based comparisons of these complex substances. Two mass spectrometer platforms are used to provide detailed characterization of glycoproteins and oligosaccharide structures. A QTOF mass spectrometer, equipped with nanospray and MALDI sources provides high resolution mass spectra of intact high molecular weight glycoproteins, such as antibodies, and determines distributions and tandem mass spectra of major derived glycans and glycopeptides. Glycans are also examined after chemical or enzymatic release of carbohydrates, liquid chromatographic separation, and MSⁿ fragmentation approaches to give detailed structural information using linear ion trap mass spectrometry and Orbitrap detection