对硫磷分子印迹膜传感器的制备及识别特性

用电聚合的方法在金电极上制备了以对硫磷为模板分子的自组装邻氨基硫酚分子印迹膜传感器.在含有5 mmol/L对硫磷模板分子、5mmol/L四丁基高氯酸铵支持电解质和30 mmol/L邻氨基硫酚的二氯甲烷的聚合液中于-0.3～1.4 V范围内循环伏安扫描30圈即得到邻氨基硫酚印迹聚合膜.结合在印迹膜上的对硫磷模板分子用0.5 mol/L HCl溶液超声20 min洗脱.循环伏安法用于电化学检测.当富集时间为10 min,磷酸盐缓冲溶液的pH=6.8时,在1.0×10-4～5.0×10-7mol/L浓度范围内与对硫磷还原峰电流成良好的线性关系,检测下限为2.0×10～mol/L.用分子印迹膜传感器对实际样品进行分析,回收率为98.0%～104%.印迹膜传感器和非印迹膜传感器对一系列与对硫磷相近似的化合物如甲基对硫磷、对氧磷、辛硫磷、氧乐果、硝基苯及邻、间、对硝基苯酚进行检测,该传感器对对硫磷具有良好的选择性和灵敏度.

Preparation and Characterization of Parathion Sensor Based on Molecularly Imprinted Polymer

A novel electrochemical sensor for the detection of parathion based on molecularly imprinted polymer of self-assembled o-aminothiophenol onto gold electrode was constructed. The polymerization solution was prepared from a 10 mmol/L parathion, 5 mmol/L tetra-n-butylammonium perchlorate, 30 mmol/L o-aminothiophenol solution of dichloromethane. Electropolymerization was carried out over 30 cycles between -0.3 V and 1.4 V. The template molecules were removed from the modified electrode surface by washing with 0.5 mol/L hydrochloric acid. Cyclic voltammetry was employed in the process of electrochemical measurements. The experimental results show that the optimum acidity of background solution is pH 6.8 and the optimum incubation time is 10 min. A highly linear response to parathion in the concentration range of 1.0 x 10(-4)--5.0 x 10(-7) mol/L is observed, with a detection limit of 2.0 x 10(-7) mol/L estimated at a signal-to-noise ratio of 3. The sensor has been applied to the analysis of parathion in real sample with recovery rates ranging from 98.0% to 104%. Parathion imprinted and nonimprinted polymer films were exposed to a series of closely related compounds, e.g. methyl-parathion, paraoxon, phoxim, omethoate, nitrobenzene and o-, m-, p- nitrophenol, and the sensor exhibited good selectivity and sensitivity to parathion.