Quantitative immunocapture MS: current status and challenges in drug discovery

Immunocapture is poised to play an increasingly vital role in therapeutic protein quantitation. In recent years, MS has emerged as an alternative to immunoassay for quantitative work. MS analysis can be achieved with or without an immunocapture step; however, the inherent selectivity of the technique typically affords LLOQ coupling immunocapture-MS methods [1]. With an ever-growing need to develop high-sensitivity assays while retaining selectivity, immunocapture followed by digestion before analysis by MS is a viable approach for protein quantitation [2,3]. Here, a brief summary on the status and challenges of protein quantitation by immunocapture followed by MS are discussed.