苄嘧磺隆分子印迹电聚合膜传感器的制备及性能研究

Preparation and characterization of a bensulfuronmethyl electrochemical sensor based on molecularly imprinted polymer membrane

以除草剂苄嘧磺隆(BSM)为模板,在金电极表面电化学聚合邻氨基苯酚(oAP)制备BSM分子印迹膜传感器。采用循环伏安法和交流阻抗技术对传感器制备过程进行表征,用紫外光谱法研究功能单体oAP和模板分子BSM间的相互作用。以K3Fe(CN)6为电化学探针,利用差分脉冲法研究了印迹膜传感器的响应性能。结果表明:V(乙腈):V(水)=1:2溶液对模板分子BSM的洗脱效果最佳,K3Fe(CN)6的峰电流值与BSM浓度在2.5~180μmol/L范围内呈现较好的线性关系(R2=0.997),检出限为0.8μmol/L。印迹膜传感器达到稳定电流响应时间约为5 min,对BSM具有较好的选择性和稳定性,能够在与BSM结构相似及常见共存物除草剂吡嘧磺隆(PSE)和特丁津(TB)的存在下选择性识别BSM。将该印迹膜传感器用于环境水样加标回收测试,回收率在95.1%~100.5%之间。

A molecularly imprinted polymer membrane electrochemical sensor for detection of herbicide bensulfuronmethyl （BSM） was constructed by electropolymerization of o - aminophenol （oAP） onto a gold electrode in the presence of herbicide BSM molecule. The imprinted electrode was prepared via cyclic voltammetric scans in the range of - 0.4 - ＋ 0. 8 V for 20 cycles in a solution consisting of 5 mL of 10 mmol/L oAP and 5 mL of 5 mmol/L BSM, which was purged with nitrogen for 5 rain before being used. The template molecule was removed by immersing the resulting electrode in an acetonitrile and deionized water （1：2, V/V） solution at room temperature under continuous agitation. The modification procedure of the imprinted sensor was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. And the intermolecular interaction between BSM and oAP was confirmed by ultraviolet spectroscopy. The recognition performance of the imprinted sensor was investigated by measuring the differential pulse voltammetric （DPV） response of the oxidation- reduction probe, K3Fe （CN）6 on the electrode. The results showed that the best eluting effect was obtained from a solution consisting of acetonitrile and water （1/2, V/V）. The peak current of K3Fe（CN）6 decreased linearly in the concentration range of BSM from 2.5 to 180 p^mol/L （ R2 = 0. 997 ） with a detection limit of 0. 8 p^mol/L . And the response time was closed to 5 min. In addition, the studied imprinted sensor exhibited high affinity and long - term stability. And the imprinted sensor demonstrated higher selectivity for target BSM over competitive, possessing analogous structures and common coexisting substance, herbicide pyrazosulfuron - ethyl （PES） and terbuthylazine （TB）. The proposed imprinted sensor was successfully applied to the determination of BSM in environmental water samples with the recoveries from 95.1% to 100. 5%.