title: Enhancement of capillary electrochromatographic separation performance by conductive polymer in a layer-by-layer fabricated graphene stationary phase.
abstract: In this work, we fabricated a novel graphene-based capillary column for open-tubular capillary electrochromatography (OT-CEC) by a layer-by-layer strategy. To immobilize graphene onto the inner surface of silica capillary, a bio-inspired method was first used to functionalize the capillary surface with a layer of polydopamine (PDA). Graphene oxide (GO) was then introduced and can covalently react with polydopamine, realizing immobilization of graphene as a result. To enhance the modification efficiency of polydopamine, a conductive polymer, polyaniline (PANI) was introduced to be a sub-layer; polydopamine was then introduced following with GO, to generate a multilayer GO-PDA-PANI@capillary. Interestingly, separation efficiency of the graphene-based capillary was enhanced significantly by using conductive PANI as a sub-layer. The morphology of different layers modified on the capillary column was characterized by scanning electron microscopy (SEM). The electroosmotic flow (EOF) characteristics of capillaries modified with different layers were also investigated by varying the pH value of mobile phase. GO-PDA-PANI@capillary showed good separation efficiency towards alkylbenzenes by OT-CEC mode, with theoretic plate numbers up to 133,918 for benzene. The separation was found to follow a reversed-phase chromatographic retention mechanism. Repeatability of the GO-PDA-PANI@capillary was studied, with relative standard deviations for intra-day and inter-day runs less than 2.89%, and column-to-column runs less than 6.17%. The separation performance of GO-PDA-PANI@capillary was also compared with that of the reported graphene modified capillary.
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China.
authors.forename: Wenpeng
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Bao
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China. Electronic address: chenzl@whu.edu.cn.
authors.forename: Zilin
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D053801:Capillary Electrochromatography / Q000295:instrumentation / Q000379:methods*; D056148:Chromatography, Reverse-Phase; D053841:Electroosmosis; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D007211:Indoles; D011108:Polymers; C416807:polyaniline; C568283:polydopamine; D012822:Silicon Dioxide; D006108:Graphite
keywords: Capillary electrocheromatography; Conductive polymer; Graphene; Layer-by-layer; Polydopamine