Optimization of Retention in Micro-Thermal Field-Flow Fractionation for the Determination of True Particle Size Distribution

Abstract

Determination of true particle size distribution of colloidal samples by field-flow fractionation requires the suppression or measurement of all contributions to the zone broadening. In order to achieve high-performance separations, experiments are often carried out at the optimal velocity of the carrier fluid at which the zone broadening due to the nonequilibrium processes is minimal. This method is traditionally used in chromatography where it was justified by classical theories. It was also applied in field-flow fractionation without raising the question on its efficiency. In this article, it is predicted theoretically and proven experimentally that high-performance separation and thus accurate determination of particle size distribution can be performed more efficiently by optimizing the experimental conditions with regard to the retention rather than to the optimal velocity of the carrier liquid.