基于制备接枝型分子印迹膜构建农药电位型电化学传感器及其检测性能研究

Design and Preparation of Molecularly Imprinted Membrane with Graft-type and Constitution of Potentiometric Sensor of Pesticides and Its Detection Performance

基于分子设计,以氯甲基化聚砜（CMPSF）为基膜,阴离子单体对苯乙烯磺酸钠（SSS）为功能单体,N,N＇-亚甲基双丙烯酰胺（MBA）为交联剂,在表面引发体系-NH2/S2O2-8的作用下,采用＂接枝聚合与分子印迹同步进行＂的分子表面印迹新技术,制备了接枝型农药抗蚜威分子印迹膜（MIM）。采用红外光谱（FITR）和光学显微镜（OM）对该分子印迹膜进行表征,通过等温结合实验与竞争吸附实验,考察了抗蚜威分子印迹膜的分子识别性能与机理。以该印迹膜作为敏感膜,构建了抗蚜威电位型传感器,并对其检测性能进行了考察。结果表明,所制备的接枝型印迹膜对模板抗蚜威分子具有特异的识别选择性和优良的结合亲和性,结合容量高达92μg/cm2,相对于分子结构与抗蚜威相似的阿特拉津,印迹膜对抗蚜威的选择性系数为4.537。在p H 4.0的水介质中,传感器膜电极的电位响应与抗蚜威浓度对数在1.0×10-6~1.0×10-3mol/L范围内呈良好的线性关系（r=0.999 9）,其检出限为2.5×10-8mol/L;以抗蚜威分子印迹膜为敏感膜所构建的电位型传感器,其构建过程简捷,检测灵敏准确,电位响应快速（t〈10 s）。

Based on molecular design,a kind of molecularly imprinted membranes with graft-type for the pesticide pirimicarb was firstly prepared by using a new imprinting technology of ＂synchronously graft-polymerizing and imprinting＂. In this process,chloromethylated polystyrene（ CMPSF） membrane was as base membrane,the anionic monomer sodium p-styrenesulfonate（ SSS） was used as functional monomer and N,N＇-methylenebisacrylamide（ MBA） was as crosslinker. By the initiating of a surface-initiating system of- NH2/ S2O2-8,the graft-polymerization /crosslinking of SSS and MBA that were combined around the template molecule of pirimicarb was realized,resulting in the pirimicarb-imprinted membrane. The imprinted membrane was characterized by infrared spectroscopy（ FITR） and optical microscope（ OM）. On this basis,the molecular recognition ability and mechanism of the imprinted membrane were examined and investigated in depth. Finally,pirimicarb- potentiometric sensor was constituted by using the pirimicarb-imprinted membrane as sensitive membrane,and the detecting performance of this potentiometric sensor was evaluated. The results show that the prepared imprinted membrane possesses the specific recognition selectivity and excellent binding affinity for the template pirimicarb molecule,and the binding capacity gets up to 92 μg / cm2.Relative to another pesticide,atrazine,whose structure is similar to that of pirimicarb in a certain degree,the coefficient of selectivity of the imprinted membrane could reach to 4. 537. In p H 4. 0 aqueous medium,this sensor offers a linear response to pirimicarb over the range of 1. 0 × 10- 6-1. 0 × 10- 3mol / L（ r = 0. 999 9） with a lower detection limit of 2. 5 × 10- 8mol / L. The potentiometric sensor constituted with pirimicarb- imprinted membrane as sensitive membrane shows the advantage of simple establishment process,sensitive detection and faster response（ t 10 s）.