乙酰胆碱酯酶/Nafion-Au-Gp-PDDA生物传感器对有机磷农药的检测

Detection of organophosphorus pesticides based on acetylcholinesterase/Nafion-Au-Gp-PDDA biosensor

目的制备乙酰胆碱酯酶/Nafion-Au-Gp-PDDA修饰玻碳电极乙酰胆碱酯酶(AChE)的酶抑制电流型传感器,用于有机磷农药的检测。方法用聚二烯丙基二甲基氯化铵(PDDA)将石墨烯(Gp)功能化,再嵌入式原位生长Au纳米颗粒,得到PDDA-Gp-Au复合材料,用原子力显微镜(AFM)表征其形貌,将其与全氟磺酸(Nafion)混匀,修饰在玻碳电极(GCE)上,用来固载AChE。采用循环伏安法(CV)检测修饰电极对底物氯化乙酰硫代胆碱(ATCL)的响应及被有机磷农药抑制后对ATCL的响应,根据抑制率与有机磷农药的浓度关系测定有机磷农药的含量,优化实验参数。结果在最优条件下,构筑的修饰电极对甲基对硫磷的线性检测范围为0.05~0.5和1.0~10.0μmol/L,检出限为10.0 nmol/L(S/N=3),并对实际工作场所空气中甲基对硫磷样品进行检测,加标回收率为97.4%~102.0%,相对标准偏差为3.05%~4.18%。结论该传感器灵敏度高,稳定性和重现性良好,且常见无机阴离子对检测无干扰,可用于实际样品的检测。

Objective A cholinesterase enzyme inhibition current sensor for the detection of organophosphorus pesticides was developed based on the preparation of acetylcholinesterase/Nafion-Au-Gp-PDDA modified glassy carbon electrode.Methods Graphene(Gp)was functionalized by polydiallydimethylammonium chloride(PDDA),and then embedded in situ growth of Au nanoparticles,PDDA-Gp-Au composite materials were obtained and characterized by atomic force microscope(AFM).Cyclic voltammetry(CV)was used to detect the response of modified electrode to the substrate acetylthiocholine chloride(ATCL)and the response to ATCL inhibited by organophosphorus pesticides.The content of organophosphorus pesticides was determined according to the relationship between the inhibition rate and the concentration of organophosphorus pesticides.Various experimental parameters were optimized.Results Under the optimal conditions,the linear detection range of methyl parathion by the modified electrode were 0.05-0.5 and 1.0-10.0μmol/L,and the limit of detection(S/N=3)was estimated to be 10.0 nmol/L.The samples of methyl parathion in the air of workplace were tested,the marked recovery rate were 97.4%-102.0%,the relative standard deviation(RSD)were 3.05%-4.18%.Conclusion The developed electrochemical sensor exhibi ts high sensitivity,good stability and reproducibility,and the common inorganic anions have no interference to the detection.It will provide a superior prospect for application.