氧化石墨烯修饰的毛细管电泳柱的制备及其在降糖药分析中的应用

摘要

目的 通过化学键合法将碳纳米材料氧化石墨烯修饰于毛细管内表面,增大比表面积,提高毛细管电泳的分离效率,扩展其应用. 方法 通过与γ-GPS硅烷化反应在毛细管内壁连接上活性基团环氧基,继续与氧化石墨烯( GO)反应,将碳纳米材料接枝于毛细管内壁. 测定并对比反应前后毛细管柱的电渗流( EOF) 来评判GO修饰柱的内表面带状态的改变,通过GO柱对几种极性不同的中性物质酚类的分离来考察其色谱能力. 测定不同pH值下电渗流的RSD%,以及日内、日间、柱间电渗流的RSD%来评估柱的稳定性及重现性. 将GO柱用于6 种降糖药的分析,扩展其应用. 结果 实验结果 表明,在GO柱中电渗流明显受抑制;几种酚类物质达到基线分离;不同pH下 EOF的 RSD%小于5.5,日内、日间、柱间EOF的RSD%分别为0.97、6.24、18.4. 在优化条件下,柠檬酸盐的缓冲液浓度为50mmol· L -1 ,pH为4.0,电压为15kV时,6种降糖药在20min内得到完全分离,柱效范围21,596~197,267 plates/m. 结论 GO被成功地修饰于毛细管内壁,增大了其内层的比表面积并提高了相比率,也体现了对苯环类化合物的色谱保留能力. 同时GO柱的重现性和稳定性良好,制柱方法 可行. 该 GO毛细管柱不仅能提高降糖药的分析效果,也有望应用于其他药物的分析检测. 为扩展毛细管电泳的应用提供了一条件途径.%OBJECTIVE A novel coated capillary was prepared by immobilizing graphene oxide ( GO) on the fused-silica capillary via covalently bonding,as a result,greater separation efficiency was achieved by the resulting column originated from the increasing specific surface area on the inner wall of the GO-capillary column.METHODS The procedure for preparing the stationary phase coating included the pretreatment of the capillary inner wall withγ-GPS via silanization,and derivatized by GO in succession.The electroosmotic flow ( EOF) characteristics of bare fused silica capillary column and GO-coated column were tested by varying the buffer pH value,and that the run-to-run,day-to-day and column-to-column reproducibilities of EOF on GO-column were evaluated with relative standard deviation values.The chromatographic properties of GO-column were investigated by separation of phenol derivatives.Furthermore, the GO-column was applied to separate 6 antidiabetic agents.RESULTS The result showed that the EOF on capillary column was definitely inhibited after modification compared with bare capillary,and it was also found that EOF RSD%of the prepared column was less than 5.5 in different acidity buffer and RSD%of intra-day,inter-day and column to column were 0.97,6.24 and 18.4%,respectively.Good separation of the tested neutral analytes ( phenols) on the GO-column was achieved.Under optimal conditions,6 hypoglycemic agents were successfully separated,and their column efficiency range was 21,596 ~197,267 plates/m.CONCLUSION The capillary was successfully modified with GO by the way as mentioned above.As a stationary phase coating,GO pro-vides not only a high surface area to increase the phase ratio but affinity interaction with aromatic organic com-pounds.In addition,the proposed column exhibits good repeatability and favorable stability.Thus,this new GO-col-umn offered a promising new alternative to the conventional capillary used in CE and may also be very useful for sep-aration science in general.