A chemical “hub” for absolute quantification of a targeted protein: orthogonal integration of elemental and molecular mass spectrometry†
Abstract
A novel element-tagged activity-based photo-cleavable biotinylated chemical “Hub” was designed and synthesized to orthogonally integrate ICP-MS and ESI-MS for absolute targeted-protein quantification. This tetrafunctional chemical “hub” allowed us to quantify a targeted protein using species-unspecific isotope dilution ICP-MS and to know which protein is being quantified using ESI-IT-MS at the same time.