Effect of Ionic Liquids as Mobile Phase Additives on Retention of Catecholamines in Reversed-Phase High-Performance Liquid Chromatography

Abstract

Ionic liquids or room temperature ionic liquids have been widely investigated as new solvents for catalysis in the past several years. Because of some special properties of ionic liquids, interest of using them in different chemical processes is increasing. This work reports on the use of 1-alkyl-3-methylimidazolium salts and N-butyl-pyridinium salts as new mobile phase additives for separation of catecholamines in reversed-phase high-performance liquid chromatography. The good separation is achieved by using these additives. Different pH values of the mobile phase, concentration of ionic liquids, and different alkyl substituents on the cations or different counterion of ionic liquids were investigated. The separation mechanism involves molecular interactions between ionic liquids and catecholamines.