Separation of monomethyl-benz[a]anthracene isomers using cyclodextrin-modified electrokinetic chromatography.
Cyclodextrin-modified electrokinetic chromatography (CD-EKC) was investigated for the separation of 12 monomethylbenz[a]anthracene (MBA) isomers. Combined use of a polymeric surfactant, poly(sodium 10-undecenyl sulfate) (poly-SUS), with various types of neutral cyclodextrins (CDs) [beta-CD, gamma-CD, dimethyl-beta-CD (DM-beta-CD), trimethyl-beta-CD (TM-beta-CD) and hydroxypropyl-beta-CD (HP-beta-CD)] were successful in CD-EKC separation of the MBA isomers. Baseline resolution of 10 of the 12 isomers, except for 9-MBA and 2-MBA, was achieved with gamma-CD at pH 9.75. The beta-CD, gamma-CD, and beta-CD derivatives (DM-beta-CD, TM-beta-CD, HP-beta-CD) were found to have different resolution and selectivity. Additionally, the tR/t0 values of isomers were found to be dependent on the type and concentration of the CD additives. In general, tR/t0 values of MBA isomers decrease with an increase in the concentration of beta-CD derivatives, whereas the reversed was true when the concentrations of native beta-CD and gamma-CD were varied. The combination of 5 mM gamma-CD, 0.5% (w/v) poly-SUS, 35% (v/v) acetonitrile at a pH of 9.75 provided the best selectivity and resolution of the MBA isomers with a separation time of 110 min. However, the use of 30 mM DM-beta-CD under similar EKC conditions resulted in much faster separation (ca. 16 min) of 10 MBA isomers.
Akbay
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Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
Shamsi
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Warner
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D001551:Benz(a)Anthracenes / Q000737:chemistry*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D003505:Cyclodextrins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D012680:Sensitivity and Specificity; D047392:beta-Cyclodextrins
D001551:Benz(a)Anthracenes; D003505:Cyclodextrins; D047392:beta-Cyclodextrins; C030935:benz(a)anthracene; C031215:betadex