This study introduces FIDA-MS, a workflow that couples Flow Induced Dispersion Analysis (FIDA) directly to native electrospray ionization mass spectrometry to screen noncovalent ligands for therapeutic protein targets without prior buffer exchange or desalting. A Fida 1 instrument was used as the front end: Taylor dispersion in an open, unpacked fused-silica capillary simultaneously performs in-line desalting from conventional, nonvolatile biological buffers and yields a size-dependent dispersion profile from which each protein's hydrodynamic radius (Rh) is measured. FIDA supplied the solution-phase Rh readout while the coupled mass spectrometer provided orthogonal gas-phase mass and charge-state information in the same run. The authors applied the automated, multiplexed method to an E3 ligase and to kinases, profiling protein samples against more than 20 candidate ligands in minutes from standard, high-salt buffers that are normally incompatible with native MS.