Retention behaviors of novel ionic liquid stationary phases and their selectivity for capillary gas chromatography

One chloride-terminated ionic liquid (CTIL) and two hydroxyl-terminated ionic liquids (HTILs) were synthesized and used as stationary phases for capillary gas chromatography (CGC). Molecular interactions of these stationary phases were evaluated by Abraham solvation parameter model, indicating that the CTIL exhibits remarkably strong H-bond basicity and the HTILs possess both H-bond basicity and acidity. The molecular interactions were further confirmed by separation of a complex mixture consisting of ketones, aldehydes, esters, alcohols and aromatic compounds. It was found that the obtained solvation parameters correlate well with the chromatographic performances of the analytes in terms of elution order and resolution. The well correlated relationship between the solvation parameters and the selectivity of the CTIL and HTILs stationary phases is quite helpful in predicting and understanding the retention behaviors of different types of analytes on these stationary phases.