A diethylenetriamine functional stationary phase, capable of complexing transition metal ions, was developed and evaluated for use in HPLC separations. An empirical retention expression was developed that related chromatographic retention to: a) electrostatic interaction of the acidic sulfonamide function with the cationic stationary phase, b) secondary metal-ligand complexations involving the heterocyclic aromatic substituents of the solutes and c) solubilization of the relatively hydrophobic solutes in the mobile phase. Retentions were inversely proportional to concentrations of organic modifier and buffer and 50% methanol was effective in minimizing electrostatic interactions while allowing retention based on metal-ligand interactions. A manuscript based on this study is in progress.
