Molecular transport and mutual diffusion measurement method in a micro-fluidic system, based on surface plasmon resonance spectroscopy

Abstract A simple experimental method to measure the mutual diffusion of molecular solutes in a micro-fluidic system has been developed. A surface plasmon resonance spectrometer measures the refractive index of a sample along the time, and thus the solute concentration can be calculated. From both, Fick´s diffusion length approach and Taylor pulse dispersion, solute and solvent diffusivities can be also obtained. Diluted alcohol-water and concentrated protein solutions were investigated. Both, the dynamic behavior and geometry effects of molecular transport have been explored numerically for the 3-dimensional case.