Abstract
In this work we elucidated the applicability of phosphonium-based ionic liquids (ILs) as pseudostationary phase in electrokinetic capillary chromatography (EKC) with UV-detection. The phosphonium ILs studied contain bromide, chlorine, or tosylate ions, as counter ions, and alkyl side chains of variable length on the phosphorous atom. The effects of the type and concentration of the IL, pH, ionic strength, and type of background electrolyte solution on the electroosmotic flow (EOF) and on the effective electrophoretic mobilities of some neutral model analytes were investigated and large variations in the migration times were observed. Especially the IL employed remarkably affected the strength and direction of the EOF Successful separations were obtained for neutral aromatic singly substituted analytes, namely benzene, toluene, phenol, and nitrobenzene. The results demonstrated the potential of capillary electromigration methods for rapid interaction studies between ILs and analytes, which is useful for the development of novel materials for sample preparation and separation purposes or for novel catalyst and chemical processing studies.
Original language | English |
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Pages (from-to) | 171-176 |
Number of pages | 6 |
Journal | Journal of Chromatography A |
Volume | 1253 |
DOIs | |
Publication status | Published - 31 Aug 2012 |
MoE publication type | A1 Journal article-refereed |
Funding
Ms Karina Moslova is acknowledged for performing the conductometric titrations. Funding from the University of Helsinki Research Funds (SKW: University of Helsinki project no. 2105060) is acknowledged.
Keywords
- Electrokinetic chromatography
- Ionic liquids
- Pseudo-stationary phase