Investigation of the effects of cyclodextrins and organic solvents on the separation of cationic surfactants in capillary electrophoresis.
The use of alpha- and beta-cyclodextrin (CD) to understand and to improve the separation of a series of cationic surfactants, homologues of alkylbenzyldimethyl ammonium compounds (ABDACs) with an alkyl chain of varying length (C10-C18), in capillary electrophoresis (CE) is reported for the first time. Similar to the effects of organic solvents, the presence of alpha- or beta-CD in the running buffer was found to reduce peak tailing/loss for the longer-chain ABDACs. Based on fluorescence measurements, it was found that formation of host-guest complexes occurred between alpha- or beta-CD and various ABDACs, with the likelihood that the hydrophobic alkyl chain including into the CD cavity and the positively charged ammonium group remaining outside the cavity. The effects of alpha- or beta-CD can be interpreted in terms of a shift away from the formation of (1) micelles in the buffer system and (2) surfactant aggregates at the fused-silica capillary walls, as a result of the formation of inclusion complexes between alpha- or beta-CD and ABDACs.
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Department of Chemistry, Hong Kong Baptist University, Kowloon Tong.
Huie
C W
CW
D002412:Cations; D003505:Cyclodextrins / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013501:Surface-Active Agents / Q000302:isolation & purification*
D002412:Cations; D003505:Cyclodextrins; D009930:Organic Chemicals; D012997:Solvents; D013501:Surface-Active Agents