Retention‐Eluent Composition Relationships of Some Polar Compounds with Imidazolium Ionic Liquid Modifiers in RP‐HPLC

Abstract

Four commonly known equations, two linear (Soczewinski and Langmuir‐type) and two quadratic, have been applied for investigation of the influence of imidazolium ionic liquids modifiers on the retention eluent composition relationships in reversed‐phase high performance liquid chromatography. In this study, three ionic liquids (1‐butyl‐3‐methylimidazolium tetrafluoroborate, 1‐ethyl‐3‐methylimidazolium methylsulfate, and 1‐octyl‐3‐methylimidazolium methylsulfate) were evaluated as mobile phase modifiers. In the experiment, nine solutes belonging to three chemical classes, and namely: nucleic compounds (uridine 5′‐monophosphate, inosine 5′‐monophosphate, guanosine 5′‐monophosphate, and hymidine 5′‐monophosphate disodium salts), nitrogen containing heterocycles (guanine and hypoxanthine), and amino benzoic acids (orthro‐, meta‐, and para‐isomers of amino benzoic acid) were tested. Evaluation of models of chromatographic retention was performed and discussed. The best correlations were achieved employing Langmuir‐type and Soczewinski equations.

Keywords:

• RP‐HPLC
• Retention model
• Mobile phase composition
• Modifier
• Ionic liquid

Acknowledgment

The authors are grateful for financial support from the Center for Advanced Bioseparation Technology, Inha University.