Hydrophilic Interaction Liquid Chromatographic (HILIC)/Ion Exchange Separation of Picolinic and Nicotinic Acids

A hydrophilic interaction liquid chromatography (HILIC)/ion‐exchange method for the analysis of nicotinic and picolinic acid is presented. Separation of nicotinic and picolinic acid was achieved at relatively high acetonitrile concentration (70%). Various aspects of the separation were examined, including buffer concentration, column temperature, buffer pH, and column configuration. Throughout the study, the method demonstrated characteristics of both ion‐exchange and HILIC retention. Studies performed indicate an increased influence of HILIC on the separation at aqueous concentrations less than 20%. Finally, a decrease in solvent consumption was noted using a small bore column without negative impact on the separation.