title: Influence of stationary phase properties on the separation of ionic liquid cations by RP-HPLC.
abstract: Different types of columns with specific structural properties were used for the separation of mixtures of ionic liquid cations. Two of them were home-made packings and the other two were commercial stationary phases. One of the home-made packings contained cholesterol ligands bonded chemically to silica (SG-CHOL) whereas the other one was a mixed stationary phase (SG-MIX) with cyanopropyl, aminopropyl, phenyl, octyl, and octadecyl ligands. RP-18e Innovation ChromolithTM Performance and Macrosphere 300 C4 packings were also used. A comparison of the separation possibilities offered by these columns for the substances in question revealed significant differences in performance. Packings containing surface-bonded functional groups that are able to undergo protonation are not suitable for separation of such compounds under the given analysis conditions (pH = 4). The best results were obtained for two alkyl stationary phases: butyl and octadecyl. Cluster analysis has also been performed for comparison of the ionic liquid cation properties.
authors.affiliation: Department of Environmental Chemistry and Ecoanalytics, Nicolaus Copernicus University, Faculty of Chemistry, Toruń, Poland. bbusz@chem.uni.torun.pl
authors.forename: Bogusław
authors.initials: B
authors.lastname: Buszewski
authors.forename: Sylwia
authors.initials: S
authors.lastname: Kowalska
authors.forename: Piotr
authors.initials: P
authors.lastname: Stepnowski