正交试验法优化制备用于小分子物质分离的聚(甲基丙烯酸缩水甘油酯-二乙烯基苯)型整体柱

以甲基丙烯酸缩水甘油酯(GMA)为单体,二乙烯基苯(DVB)为交联剂,以环己醇和正十二醇为致孔剂,过氧化苯甲酰(BPO)为引发剂,直接以50 mm×4.6 mm色谱柱为模具,通过原位聚合制备聚(GMA-DVB)型整体柱。以GMA和DVB的体积比、环己醇和十二醇的体积比以及BPO占聚合物的质量分数为三因素,以分离苯和乙苯等小分子物质时的半峰宽分离度(R1/2)为考察指标,进行三因素三水平的正交试验,通过测定整体柱的比表面积、孔径和孔容分布对其进行表征。结果表明,制备整体柱的最优配方为V(GMA): V(DVB): V(环己醇): V(正十二醇)=0.825:0.825:1.32:2.03, BPO的质量分数为0.7%。应用所制备的整体柱分离苯和乙苯等小分子物质,理论塔板数达到37000塔板/m, R1/2值达到7.14,完全达到基线分离,分离时间小于10 min。该方法制备整体柱的重复性好,柱效较高,基本满足商品化要求。

Optimization of preparation of poly (glycidyl methacrylate- divinylbenzene) monolithic column with orthogonal experiments for separation of small molecules

A monolithic column of macro porous poly(glycidyl methacrylate-divinylbenzene) (poly(GMA-DVB)) has been prepared by free radical polymerization within the confines of a chromatographic stainless steel tube (50 mm×4.6 mm).For the best separation and low back pressure,orthogonal experiments were carried out with V(cyclohexanol)∶ V(dodecanol),V(GMA)∶ V(DVB) and BPO dosage as the three main factors.The characteristic feature of the column,including specific surface area,pore volume as well as pore diameter distribution,was studied by scanning electron microscopy (SEM),mercury intrusion porosimetry analysis and BET analysis.The obtained optimum preparation conditions were that the volume ratio of GMA,DVB,cyclohexanol and dodecanol was 0.825∶0.825∶1.32∶2.03 and the BPO dosage was 0.7%(mass percentage),then it was heated at 70 ℃ for 24 h.Using this monolithic column,benzene and ethylbenzene and a drug of oxiracetam can be well separated on a high performance liquid chromatographic (HPLC) system equipped with a ultraviolet (UV) detector at 254 nm.A solution of acetonitrile-water (50∶50,v/v) for the separation of benzene and ethylbenzene,and acetonitrile-water (80∶20,v/v) for the separation of oxiracetam were used as mobile phases at a flow rate of 1 mL/min.The theoretical plate number was 37 000 plates/m and the resolution of peak width at half height (R_(1/2)) was 7.14.The separation time was less than 10 min.The monolithic column prepared by this method is reproducible and has high column efficiency.It is an economical method to prepare monolithic column,which can be applied to separate small molecules.