Description of solute retention over the full range of mobile phase compositions in reversed-phase liquid chromatography

Abstract

In this paper we investigate the relationship between solute retention and mobile phase composition in reversed-phase liquid chromatography over the entire range of composition, with emphasis on mobile phases with a high water content. It will be shown that a quadratic relationship between the logarithm of the capacity factor and the volume fraction of organic modifier is generally valid for mobile phases containing less than 90% water. When more water is added to the mobile phase, a quadratic equation turns out to be insufficient. An experimental study of ten solutes and three organic modifiers is used to show that an extension of the quadratic equation by a term proportional to the square root of the volume fraction leads to a description of all experimental retention data within approximately 10%.