Poly(divinylbenzene-alkyl methacrylate) monolithic stationary phases in capillary electrochromatography.
In this study, a series of poly(divinylbenzene-alkyl methacrylate) monolithic stationary phases, which were prepared by single step in situ polymerization of divinylbenzene and various alkyl methacrylates (butyl-, octyl-, or lauryl-methacrylate), were developed as separation columns of benzophenone compounds for capillary electrochromatography (CEC). In addition to the presence of plenty of benzene moieties, the stationary phases contained long and flexible alkyl groups on the surface. With an increase in the molecular length of alkyl methacrylate, the polymeric monolith, which had higher hydrophobicity, effectively reduced the peak tailing of benzophenones, but a weaker retention was observed. The unusual phenomenon was likely due to the pi-pi interaction between the aromatic compound and the polymeric material. The usage of longer alkyl methacrylate as reaction monomer limited the retention of aromatic compounds on the stationary phase surface, thus the pi-pi interaction between them was possibly reduced. Consequently, the retention time of aromatic compounds was markedly decreased with an increase in carbon length of alkyl methacrylate that was carried on the polymeric monolith. Compared to previous reports on polystyrene-based columns in which the peak-tailing problem was reduced by decreasing the benzene moieties on the stationary phase, this study demonstrated that the undesirable retention (peak-tailing) could also be improved by the inclusion of long alkyl methacrylate to the polystyrene-based columns.
Huang
Hsi-Ya
HY
Department of Chemistry and Center for Nanotechnology, Chung Yuan Christian University, 200 Chung Pei Road, Chung-Li 320, Taiwan. hyhuang@cycu.edu.tw
Cheng
Yi-Jie
YJ
Liu
Wan-Ling
WL
Hsu
Yi-Fen
YF
Lee
Szetsen
S
D001577:Benzophenones / Q000737:chemistry; D053801:Capillary Electrochromatography / Q000379:methods*; D003511:Cyclohexanols / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry*; D008853:Microscopy; D011137:Polystyrenes / Q000138:chemical synthesis / Q000737:chemistry*; D016062:Porosity; D011760:Pyrrolidinones / Q000737:chemistry; D015203:Reproducibility of Results; D014753:Vinyl Compounds / Q000737:chemistry*
D001577:Benzophenones; D003511:Cyclohexanols; D008689:Methacrylates; D011137:Polystyrenes; D011760:Pyrrolidinones; D014753:Vinyl Compounds; C432006:divinylbenzene-polystyrene copolymer; C004985:divinyl benzene; C038678:N-methylpyrrolidone