SPE-MALDI Profiling of Serum Peptides and Proteins by Ultrahigh Resolution FTICR-MS

Abstract

Mass spectrometry (MS)-based profiling of serum peptides for biomarker discovery purposes and comparative analyses of clinical cohorts has been widely applied on surface-enhanced laser desorption/ionization- and matrix-assisted laser desorption/ionization (MALDI)-platforms. Most commonly, these strategies involve a single-step sample clean-up procedure and time-of-flight MS readout. Previously, we have developed fully automated high-throughput magnetic bead-based solid-phase extraction (SPE) procedures to enable peptide and protein profiling studies. In this study, it will be shown that the combination of SPE with MALDI and ultrahigh resolution Fourier transform ion cyclotron resonance MS provides a next-generation platform that allows such profiling up to molecular weights of 15 kDa with full isotopic resolution for each species. Beneficial aspects of using ultrahigh resolution MS for MALDI profiling are mass precision and spectral alignment, resolving overlapping signals, and identification (structure characterization) of differentiating features.