2-异戊基环戊酮虚拟模板印迹微球的制备及其吸附性能

Preparation of Novel Molecularly Imprinted Microsphere by Using 2-Isopentyl Cyclopentanone as the Dummy Template and Its Adsorption Behavior

以2-异戊基环戊酮为虚拟模板,采用沉淀聚合法制备了粒径20~50μm的分子印迹微球。用傅里叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)研究了分子印迹微球的表面化学特征及粒径分布,测试了印迹聚合物对玫瑰醚的吸附动力学、等温吸附性能及吸附选择性。考察了分子印迹固相萃取玫瑰醚的应用效能。结果表明:分子印迹聚合物(MIPs)对玫瑰醚的吸附可在25 min达到平衡,具有较快的吸附动力学,一级动力学模型更适合描述其吸附动力学行为。Freundlich模型最适合描述MIPs对玫瑰醚的等温吸附行为,聚合物材料最大的印迹位点数目为149.3μmol/g。聚合物对玫瑰醚的平均吸附能为166 kJ/mol,表明主要为化学吸附。虚拟模板印迹聚合物对玫瑰醚的选择因子相对于香叶醇和香茅醇分别为3.710和5.636,且对含玫瑰醚的混合物中的目标化合物仍具有较高的选择吸附能力(竞争吸附量为18.02 mg/g)。在优化洗涤(1 mL乙腈+1 mL乙腈和水混合溶剂(体积比9.5∶0.5)+2 mL乙腈、甲醇和水混合溶剂(体积比8∶1∶2)和洗脱(3 mL甲醇和醋酸混合溶剂(体积比9∶1))条件下,通过分子印迹固相萃取可实现玫瑰醚的有效分离和富集,回收率为96.23%。

Novel molecularly imprinted polymer(MIP)microspheres were prepared by the precipitation polymerization method using 2-isopentyl cyclopentanone as the dummy template.The surface chemical groups were characterized by Fourier transform infrared spectroscopy(FTIR)and the particle size distribution was characterized by scanning electronic microscope(SEM).Adsorption dynamics,isotherm adsorption behavior and application capacity for this MIP in solid phase extraction of rose oxide were explored.The results indicated that MIPs could reach adsorption equilibrium within 25 min,showing a rapid adsorption dynamics,and the first order model was better to describe its adsorption dynamics behavior.Additionally,the Freundlich isotherm model was more suitable to describe the isotherm adsorption behavior and a maximum binding site number(149.3μmol/g)was obtained by fitting the isotherm data to the Langmuir model.A mean adsorption potential energy of 166.7 kJ/mol indicated a chemical adsorption process for MIPs.The selectivity factor for MIPs toward rose oxide relative to geraniol and citronellol was 3.710 and 5.636,respectively.Especially,this MIP possessed higher competitive adsorption capacity toward rose oxide in the mixture,with an adsorption capacity of 18.03 mg/g.Under the optimized solid phase extraction conditions,i.e.,washing by using 1 mL acetonitrile,1 mL acetonitrile-water mixture(volume ratio 9.5∶0.5)and 2 mL acetonitrile-methanol-water mixture(volume ratio 8∶1∶2)and eluting by using 3 mL methanol-acetic acid mixture(volume ratio 9∶1),rose oxide can be separated and enriched from crude rose extract by using molecularly imprinted polymeric solid phase extraction,with a recovery of 96.23%.