ABSTRACT
This chapter provides the reader with an update on the most recent developments in fundamental understanding of retention mechanisms in chaotropic chromatography and in the wide range of its practical applications in drug analysis. It gives a phenomenological description of the putative retention mechanisms in chaotropic chromatography, with emphasis on how chaotropic agents behave in an reversed-phase high-performance liquid chromatography (RP-HPLC) system, and modulates the retention behavior of charged analytes. The chapter presents an overview of the equilibria that exist in the resulting complex chromatographic system. It gives a critical overview of the theoretical approaches that can be used to model the retention behavior in chaotropic chromatography. The chapter summarizes key empirical findings related to how mobile phase composition, choice of the chaotropic agent, and the chromatographic column affect retention phenomena. It also provides a review of emerging attempts to describe and rationalize the influence of analytes' structure on its retention in chaotropic chromatography through quantitative structure–retention relationship (QSRR) modeling.
