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

摘要

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.