After graduating with a B.S. in chemistry, Xibei Dang studied ultra-high resolution mass spectrometry with FTICR under Dr. Alan Marshall at Florida State University. Her research focused on top-down analysis of protein sequence variants and Post-translational Modifications (PTMs). After graduate school she join the Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolomics (PPDM) at Merck. Currently she is an Associate Principle Scientist in the discovery bioanalysis group in PPDM at Merck Research Laboratory, South San Francisco. Her main responsibility is characterization and quantitation of large molecule drug candidates and biomarkers in pre-clinical space using LC-MS to inform protein engineering and decision making.