氨基脲分子印迹电化学传感器的制备及应用

Preparation and Application of Semicarbazide Electrochemical Sensor Based on Molecularly Imprinting Technique

以氨基脲（SEM）为模板分子邻苯二胺为功能单体,在0.1 mol/L NaAc-HAc缓冲液（pH 5.2）中,通过电聚合法制备分子印迹传感器。采用循环伏安法（CV）、差分脉冲法（DPV）、电化学阻抗谱（EIS）和扫描电镜表征了此分子印迹传感器的识别性能和表面形貌。结果表明,此传感器具有粗糙、多孔的形貌,对SEM具有良好的选择性识别。在0.5 mol/L KCl-0.005 mol/L K3[Fe（CN）6]溶液中,采用DPV方法考察了功能单体与模板分子的摩尔比、模板洗脱剂、洗脱时间和温育时间对传感器响应的影响。优化后的实验条件为：功能单体与模板分子的摩尔比1：2,洗脱液为0.2 mol/L NaOH,洗脱时间15 min,温育时间12 min。在优化的实验条件下,传感器的DPV峰电流差值与SEM的浓度在3.75-188 ng/L范围呈良好的线性关系,检出限为1.5 ng/L（S/N=3）。将此传感器应用于市售新鲜虾肌肉及受污染虾肌肉中SEM含量测定,加标回收率为80%-97%。

A molecularly imprinted electrochemical sensor was prepared by electropolymerization using semicarbazide（SEM） as template molecule and o-phenylenediamine as functional monomer in 0.1 mol/L NaAc-HAc buffer solution（pH 5.2）.The performance and surface feature of the proposed imprinted sensor was investigated using cyclic voltammetry（CV）,differential pulse voltammetry（DPV）,electrochemical impedance spectroscopy（EIS） and scanning electron microscope.The sensor had a rough and porous surface morphology,and showed good recognition and selectivity to SEM.The sensor performance was optimized by using DPV method in 0.5 mol/L KCl solution with 5 mmol/L K3[Fe（CN）6]as the electron transport medium.The optimized conditions were that the molar ratio of functional monomer to template molecule was1：2,the elution liquid was 0.2 mol/L NaOH,and elution and incubation time was 15 and 12 min,respectively.The DPV peak current difference of the sensor had a linear relationship with the concentration of SEM in the range of 3.75 - 188 ng/L and the detection limit was 1.5 ng/L（S/N = 3）.The prepared imprinted sensor was used to detect SEM in commercially available fresh shrimp muscles as well as shrimp contaminated with drugs with satisfactory results,and the recoveries of SEM were in the range of 80%-97%.