SEPARATIONS OF ALKYL-SUBSTITUTED ANTHRACENES USING CYCLODEXTRIN DISTRIBUTION CAPILLARY ELECTROCHROMATOGRAPHY

Alkyl-substituted anthracenes were separated using a technique dubbed cyclodextrin distribution capillary electrochromatography (CDCE). Nati ve beta- or gamma-cyclodextrins (CDs), in conjunction with carboxymeth yl-beta-cyclodextrin (CM-beta-CD) or sulfated-beta-cyclodextrin (Su-be ta-CD), were employed in running buffers to create a dual-CD-phase sys tem. In this system, analytes are separated based upon their different ial distribution between the neutral CDs (beta-CD or gamma-CD) moving with the bulk electroosmotic flow and electrophoretically mediated, ch arged CDs (CM-beta-CD or Su-beta-CD). Comparisons are drawn between CD CE and CD-modified micellar electrokinetic capillary chromatography. C DCE is shown to provide unique selectivity and good resolution of meth yl-ethyl-substituted anthracenes. Control of retention is possible thr ough varying the concentrations and types of CDs employed. Laser-induc ed fluorescence provides detection limits in the low-to-subparts per b illion range. Field strength and total CD concentration exert a substa ntial influence on the observed plate height. Analysis of CM-beta-CD w ith capillary electrophoresis reveals information about composition (r ange of degree of substitution) of the derivatized CD phase. Molecular modeling is also employed to investigate that position of CM substitu tion has on the shape of the CD. (C) 1996 John Wiley & Sons, Inc.