title: Carbon nanotube/poly(ethylene-co-vinyl acetate) composite electrode for capillary electrophoretic determination of esculin and esculetin in Cortex Fraxini.
abstract: In this report, a novel carbon nanotube/poly(ethylene-co-vinyl acetate) (CNT/EVA) composite electrode was developed for the amperometric detection in CE. The composite electrode was fabricated by packing a mixture of CNTs and melted EVA in a piece of fused-silica capillary under heat. It was coupled with CE for the separation and detection of esculin and esculetin in Cortex Fraxini, a traditional Chinese medicine, to demonstrate its feasibility and performance. Esculin and esculetin have been well separated within 9 min in a 40 cm long capillary at a separation voltage of 12 kV using a 50 mM borate buffer (pH 9.2). The new CNT-based CE detector offered significantly lower detection potentials, yielded enhanced S/N characteristics, and exhibited high resistance to surface fouling and enhanced stability. It showed long-term stability and reproducibility with relative standard deviations of less than 5% for the peak current (n=15) and should also find a wide range of applications in other microfluidic analysis systems.
authors.affiliation: School of Pharmacy, Fudan University, Shanghai, P. R. China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Luyan
authors.initials: L
authors.lastname: Zhang
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
mesh_terms: D031319:Aesculus; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D004929:Esculin / Q000032:analysis*; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000648:ultrastructure; D011145:Polyvinyls / Q000737:chemistry; D012680:Sensitivity and Specificity; D014468:Umbelliferones / Q000032:analysis*
chemical_list: D004365:Drugs, Chinese Herbal; D037742:Nanotubes, Carbon; D011145:Polyvinyls; D014468:Umbelliferones; D004929:Esculin; C016438:ethylenevinylacetate copolymer; C517354:horse chestnut seed; C007628:esculetin