Capillary electrophoresis mass spectrometry for the identification of aminopyrene trisulfonic acid labeled glycans The aim of this work was the development of capillary electrophoresis mass spectrometry (CE MS) methods with high separation power for the characterization of aminopyrene trisulfonic acid (APTS) labeled glycans. State of the art for routine glycan analysis is capillary sieving electrophoresis with laser induced fluorescence detection (CSE LIF) using the fluorescent APTS. However a firsthand identification of glycans is not possible. This thesis presents two high performance CE MS methods with appropriate separation efficiency (i.e. resolution of structural isomers) for biopharmaceutical samples. The first method uses a novel alkaline background electrolyte (BGE) for the simultaneous analysis of APTS labeled as well as charged native glycans. The alkaline BGE enables a robust CE MS application and the determination of derivatization and ionization efficiency. The glycans of several different types of biopharmaceutically relevant proteins could be identified. ...