14CBMS. We introduce an approach that overcomes the limitations of conventional analysis methods by exploiting surface complexation interactions that emerge when a micron-scale chemical discontinuity is created between suspended nanoparticles and a fluorescent tracer. The generated fluorescence signature is easily detectable and inherently reveals quantitative information about composition, quantity, size, and morphology of nanoparticles in suspension independent of their agglomeration state. We demonstrate our method by establishing the capability to perform continuous characterization of commercial ZnO, anatase and rutile TiO
2nanoparticles. We formulate a reaction-diffusion model to verify experimental findings and capture the fundamental underlying transport and adsorption phenomena.