对羟基苯甲酸印迹聚合物微粒的制备及其固相萃取应用

以对羟基苯甲酸(p-HBA)为模板分子,丙烯酰胺(AM)为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用沉淀聚合法在乙腈溶剂中制备了p-HBA印迹聚合物微粒,研究了p-HBA加入量及聚合反应体系的总浓度对印迹聚合物结合性能的影响,采用色谱法对其进行了评价。结果表明,p-HBA的加入量及反应体系的总浓度对结合性能均有影响,当p-HBA加入量为1.0 mmol(与AM物质的量比为1:2)时,在37.5 mL乙腈中制得印迹聚合物P₂对p-HBA具有高的亲和力(k'=4.01)和选择性。将印迹聚合物P₂作为固相萃取填料,研究了分子印迹固相萃取p-HBA的方法,测得2种不同载样模式下p-HBA的柱容量分别为6.91 μg/100 mg和1.93 μg/100 mg,测得天麻样品中p-HBA的加标回收率为76.8%~86.6%(RSD=3.4%~6.2%)(n=3)。结果表明,采用沉淀聚合法以AM为功能单体制备的p-HBA印迹聚合物微粒适宜作为固相萃取填料,可实现天麻样品中p-HBA的选择性分离净化。

Preparation of p-Hydroxybenzoic Acid-Imprinted Polymer Particulates and Application to Solid Phase Extraction

p-Hydroxybenzoic acid(p-HBA)-imprinted polymer particulates were prepared using p-HBA as the template, acrylamide(AM) as the functional monomer and ethylene glycol dimethacrylate as the crosslinker in three different amounts of p-HBA and under two different concentrations of pre-polymerization mixtures via precipitation polymerization. Their rebinding performances for p-HBA were characterized by high-performance liquid chromatography. The results reveal that both the amounts of p-HBA and the concentrations of pre-polymerization mixtures exhibit notable influence on the binding performances of p-HBA-imprinted polymers. The p-HBA-imprinted polymer(P₂) with high affinity(k'=4.01) and selectivity for p-HBA is obtained when the amount of p-HBA is 1.0 mmol, which is corresponding to the molar ratio of 1:2(p-HBA/AM), in 37.5 mL of acetonitrile solvent. In addition, the imprinted polymer P₂ was chosen as the adsorbent to make the molecularly imprinted solid phase extraction(MISPE) column and the MISPE method for the extraction of p-HBA was developed. The MISPE column capacities for p-HBA are 6.91 μg/100 mg and 1.93 μg/100 mg, respectively, which are determined under two different modes of loading samples. The rhizoma gastrodiae samples spiked with three different amounts of p-HBA are extracted and the recoveries of p-HBA range from 76.8% to 86.6%, with the RSD of 3.4%~6.2%(n=3). The results demonstrate that the p-HBA-imprinted polymer particulates prepared using AM as the functional monomer by precipitation polymerization are suitable as the adsorbent of solid phase extraction column for the selective separation and purification of p-HBA in the real sample of rhizoma gastrodiae.