LC–HRMS quantitation of intact antibody drug conjugate trastuzumab emtansine from rat plasma

Current LC–MS for protein quantitation is mostly based on enzymatic digestion of the target protein followed by quantitation of a signature peptide in the presence of a stable-isotope-labeled peptide as the internal standard (IS) [1,2]. Compared with peptide level quantitation of proteins, LC–MS quantitation of proteins at intact level presents many challenges in both LC and MS, especially for larger proteins such as antibodies and antibody–drug-conjugates (ADCs) [3]. Due to the size, structure complexity and heterogeneity of larger proteins, it is more challenging to obtain good chromatography for their LC–MS analysis [4]. Reverse phase LC which is widely used in...