Diffusion coefficient measurements by the chromatographic method

Abstract

This paper reviews advances in the theory and implementation of the chromatographic method for diffusion-coefficient measurements in the liquid phase. It is shown that by means of a proper design an instrument can be constructed which conforms very nearly to the simplest model of it, so the remaining small departures from the model can be taken into account. An instrument for the measurement of liquid-phase diffusion coefficients with an accuracy of ±1% is described and some results for the mutual diffusion coefficients of normal alkane mixtures are presented which confirm the correct operation of the instrument. Exploratory work on the application of the chromatographic method to self-diffusion coefficient measurements of ions in solution, and mutual-diffusion coefficients near a liquid–liquid critical point is briefly discussed.