Retention Model for Anionic, Neutral, and Cationic Analytes in Reversed-Phase Ion Interaction Chromatography

摘要

A model for the prediction of retention data for 1- and 2-charged analytes in ion interaction chromatography, previously developed by our group, has been extended to account for the retention behavior of cationic and neutral analytes. By using a single mathematical procedure, it is possible to develop applicative equations to describe the simultaneous effect of the concentration of ion interaction reagent, organic modifier, and counterion on the capacity factor k' of analytes with different charges(neutral, negative, and positive). The modeling considers the retention process as a result of several adsorption and ion exchange equilibria, whose constants can be calculated by an iterative method of nonlinear regression. The applicability pf the equation developed has been tested on different classes of organic (aromatic sulfonates and carboxylic acids) and inorganic analytes. The experimental design has been planned in order to describe the chromatographic behavior as a function of the mobile phasecomponents: cetyltrimethylammonium chloride, sodium chloride, and methanol.