College of Chemistry, Jilin University, Qianjin Street 2699#, Changchun 130012, China.
J Chromatogr A. 2012 Aug 31;1253:22-31. doi: 10.1016/j.chroma.2012.07.003. Epub 2012 Jul 7.
Novel monolithic capillary columns with embedded graphene were developed and used for polymer monolith microextraction (PMME) coupled to LC-MS analysis. The column was prepared inside fused silica capillaries (320 μm, i.d.) using thermally initiated free-radical polymerization with butyl methacrylate (BMA) as monomer, ethylene dimethacrylate (EDMA) as cross-linker, and 1,4-butanediol and 1-propanol as porogens. Graphene (GN) was incorporated into the poly(BMA-EDMA) monolith to enhance the loading capacity. The obtained GN and the poly(BMA-EDMA-GN) monolith were characterized by transmission electron microscope (TEM), atomic force microscopic (AFM) and scanning electron microscopy (SEM). The extraction performance of the monolithic column was evaluated by glucocorticoids (GCs) as the analytes. The operation parameters of PMME including desorption solvent, sample flow rate, sample volume, sample pH, and eluent flow rate were studied and optimized. When compared to the parent poly(BMA-EDMA) column and direct sample analysis, high enrichment capacity was observed in the case of GN-entrapped monolith. The GN incorporated monolithic capillary showed satisfactory reusability and stability during extraction. The limits of detection (S/N=3) for nine GCs were in the range of 0.13-1.93 ng/mL. Relative standard deviations for the determination of the target GCs were less than 14.5%. Finally, the PMME method, based on the developed monolithic capillary as the extraction media, was successfully applied to the determination of nine GCs in cosmetics. The recoveries of GCs spiked in different matrices ranged from 83.7% to 103.8%.
新型整体式毛细管柱嵌入了石墨烯，用于聚合物整体微萃取（PMME）与 LC-MS 分析相结合。该柱是在熔融石英毛细管（320μm，内径）中使用热引发自由基聚合制备的，单体为甲基丙烯酸丁酯（BMA），交联剂为二甲基丙烯酸乙二醇酯（EDMA），1,4-丁二醇和 1-丙醇为致孔剂。将石墨烯（GN）掺入聚（BMA-EDMA）整体中以提高负载能力。通过透射电子显微镜（TEM）、原子力显微镜（AFM）和扫描电子显微镜（SEM）对获得的 GN 和聚（BMA-EDMA-GN）整体进行了表征。通过将糖皮质激素（GCs）作为分析物来评估整体柱的萃取性能。研究并优化了 PMME 的操作参数，包括解吸溶剂、样品流速、样品体积、样品 pH 值和洗脱液流速。与母体聚（BMA-EDMA）柱和直接样品分析相比，GN 包埋的整体柱表现出更高的富集能力。GN 掺入的整体毛细管在萃取过程中表现出令人满意的可重复使用性和稳定性。九种 GCs 的检测限（S/N=3）范围为 0.13-1.93ng/mL。目标 GCs 测定的相对标准偏差小于 14.5%。最后，基于开发的整体毛细管作为萃取介质的 PMME 方法成功应用于化妆品中九种 GCs 的测定。在不同基质中添加 GCs 的回收率范围为 83.7%-103.8%。
