聚环糊精-碳纳米管有机磷农药生物传感器

Electrochemical biosensor based on composite film of polycyclodextrin and CNT for detection of organophosphorus pesticides

通过环糊精的聚合反应及其对碳纳米管的分散作用制备出不溶于水的聚环糊精-碳纳米管复合导电修饰材料,把CNT的稳定性、导电性和催化活性与环糊精分子的包络作用及生物相容性结合起来,得到一种可用于制备电化学生物传感器的碳纳米管-聚合物复合材料。在此基础上,通过优化固定化方法,在该复合材料上固定乙酰胆碱酯酶,制备出了灵敏度较高、线性范围较宽的有机磷农药生物传感器,该传感器可以在1.0~15.0 mg/L浓度范围内检测农药甲胺磷的含量,检测下限为0.05 mg/L。利用不同扫描速度下的循环伏安数据分析了传感器的电极反应机理,发现该传感器的电极过程由扩散步骤和电子转移步骤混合控制。

An amperometric biosensor for the detection of organophosphorus pesticides（OPs） was fabricated and tested.The insoluble conducting composite film of poly-cyclodextrin（CDP） containing carbon nanotube（CNT） was synthesized.Cyclic voltammetry measurements in potassium ferricyanide solution（50 mmol/L,and scan rate 50 mV/s） show that the film maintains the distinct physical properties of CNT,such as high electrical conductivity,chemical stability and electrocatalytic activity.Also the film maintains the specialities of β-CD,such as inclusion performance and biocompatibility.The film was used to fabricate organophosphorus pesticides biosesors by immobilizing acetylcholinesterase（AChE）.The fabricated biosensors via the composite film of CDP and CNT have many advantages such as electronic activity,good stability,excellent biocompatibility,etc.It could be operated under low voltage.Amperometric measurements were done in acetylthiocholine chloride solution with different concentrations of methamidophos.The biosensors have wide concentration ranges and good sensitivity to methamidophos.The inhibition rates of the sensor increased with the concentration of methamidophos,and the fitting curve of inhibition rates versus the logarithm of concentration is linear over the concentration ranges between 1.0 and 15.0 mg/L with RSD = 0.992.The detection limits to methamidophos of the sensor is calculated to be 0.05 mg/L.Cyclic voltammetry measurements shows a mixed controlled electrode reaction.