Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China.
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China.
J Chromatogr A. 2014 Apr 25;1339:192-9. doi: 10.1016/j.chroma.2014.02.083. Epub 2014 Mar 5.
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.
在这项工作中，我们通过层层策略制造了一种新型基于石墨烯的开管毛细管电色谱（OT-CEC）用毛细管柱。为了将石墨烯固定在硅胶毛细管的内表面上，首先使用一种仿生方法用聚多巴胺（PDA）层对毛细管表面进行功能化。然后引入氧化石墨烯（GO），并与聚多巴胺发生共价反应，从而实现石墨烯的固定化。为了提高聚多巴胺的修饰效率，引入了一种导电聚合物聚苯胺（PANI）作为亚层；然后引入聚多巴胺和 GO，生成多层 GO-PDA-PANI@capillary。有趣的是，使用导电 PANI 作为亚层可显著提高基于石墨烯的毛细管的分离效率。通过扫描电子显微镜（SEM）对毛细管柱上不同层的形貌进行了表征。还通过改变流动相的 pH 值研究了不同层修饰的毛细管的电渗流（EOF）特性。GO-PDA-PANI@capillary 在 OT-CEC 模式下对烷基苯表现出良好的分离效率，苯的理论塔板数高达 133918。分离被发现遵循反相色谱保留机制。研究了 GO-PDA-PANI@capillary 的重现性，日内和日间运行的相对标准偏差小于 2.89%，柱间运行的相对标准偏差小于 6.17%。还将 GO-PDA-PANI@capillary 的分离性能与报道的石墨烯修饰毛细管的分离性能进行了比较。
