We performed a systematic study on titania, ceria, and silica nanopowders, to investigate their interactions with ligands and the corresponding colloidal stability in aqueous solutions. Electrospray-differential mobility analysis (ES-DMA) was employed for characterization of particle size distributions (PSDs), including the peak diameter (d(p,m)*) and the full width at half maximum (FWHM) of nanoparticle suspensions. Transmission electron microscopy and zeta potential analysis were employed orthogonally to provide information of particle imagery and surface charge, respectively. Bovine serum albumin, sodium dodecyl sulfate, and cetyltrimethylammonium bromide were chosen as representative ligands. Results show that we were able to successfully characterize the ligand-nanoparticle interaction including the aggregation, de-aggregation, and the surface dissolution of nanoparticle using ES-DMA. Based on the measured d(p,m)*, FWHM, and the number concentrations over various experimental conditions, we observed that the colloidal stability was strongly dependent of the environmental pH, isoelectric point (IEP) of nanoparticle, and the acid dissociation constant (pK(a)) of ligand. Fast aggregation was found when the absolute zeta potential of nanoparticles was below 18 mV and/or X (defined as [(IEP + pK(a))/2 - pH]) < 2. Our work demonstrates a prototype study for establishing the capability of characterizing ligand-nanoparticle interactions and developing a correlation to the corresponding colloidal stability in a variety of aqueous environments (e.g., formation chemistry, natural water system). (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.