首次以氯甲基化交联聚苯乙烯树脂(CMCPS)为载体和大分子引发剂、2,4-二氯苯氧乙酸(2,4-19)为模板、丙烯酰胺(AM)为单体、乙二醇二甲基丙烯酸酯(EDMA)为交联剂、溴化铜/2,2’-联吡啶(CuBr/Bpy)为催化剂,采用表面引发原子转移自由基聚合(SI-ATRP)技术,制备了2,4-二氯苯氧乙酸分子印迹聚合物(2,4-DMIPs),并研究了模板分子与功能单体比例对该印迹聚合物吸附量的影响。通过动态、静态及竞争试验考察了该印迹聚合物对2,4-D的吸附性能。结果表明:2,4-DMIPs对模板分子2,4-D具有良好的特异性识别作用;与2,4-二氯苯酚和2,4-二氯苯甲醛相比,2,4.DMIPs对2,4-D的选择性系数分别为2.84和3.75,相对选择性系数分别为2.31和2.29。采用Scatchard模型分析,可以得到两类结合位点,计算得到最大表观吸附量(Qmax)分别为76.92和142.91mg/g,离解常数亿分别为632.91和2309.47mg/L。将2,4-DMIPs作为固相萃取剂,对豆芽样品进行添加回收试验,回收率为86%-104%,相对标准偏差(RSD)为1.9%~10%,方法的检出限为20ng/g。该印迹聚合物可以富集分离测定2,4.D,稳定性好,并且能重复使用。
2,4-Dichlorophenoxyacetic acid imprinted surface-initiated atom transfer radical polymerization materials (2,4-D MIPs ) were prepared by ( SI-ATRP ) method. With chloromethyl polystyrene resin (CMCPS) as carrier and macro-initiator, the imprinted polymers were synthesized byusing 2,4-D as template, acrylic amide as functional monomer and ethylene glycol dimethacrylate (EDMA) as cross-linker, and CuBr/2, 2'-bipyridine (CuBr/Bpy) as the catalytic system. The influence of ratio of template and monomer on the adsorption capacity of 2,4-D MIPs was discussed in details. The binding properties of 2,4-D MIPs for 2,4-dichlorophenoxyacetic acid were studied with both static and dynamic experimental methods. The results showed that 2,4-D MIPs had specific recognition selectivity and excellent binding selectivity for the template molecule. In respect to 2,4- dichlorophenol and 2,4-dichlorobenzaldehyde, its selectivity coefficient to 2,4-D were 2. 84 and 3.75, with relative selectivity coefficient 2.31 and 2. 29. From the Scatchard analysis, Qmax (the apparent maximum binding amount) values were calculated to be 76.92 and 142.91 mg/g, respectively, and Kd (the dissociation constant) values were 632.91 and 2 309.47 mg/L. Using 2,4-D MIPs as solid phase materials, the fotified recoveries were among 86%-104%, with relative standard deviations (RSDs) of 1.9%-10%, and the limit of detection (LOD) in the bean sprout samples reached 20 ng/g. In conclusion, these imprinted materials can be used for enrichment or separation of trace amounts of 2,4-D, with merits of good stability, simple handling.