球壳TiO_(2)-吡咯共聚膜的制备及吡虫啉测定

Preparation of copolymerized film based on hollow TiO_(2) nano-shell-pyrrole for the determination of imidacloprid

通过水热模板法制备壁厚约10 nm的TiO2纳米球壳(HTNs),采用电化学法在0~0.6 V范围内与吡咯(Py)共聚修饰ITO电极,制备HTNs-PPy/ITO传感器。考察聚合缓冲液的pH对共聚膜硬度和电化学性能的影响,运用扫描电镜和透射电镜对HTNs和HTNs-PPy/ITO传感器表面进行表征。比较裸电极ITO、聚吡咯修饰电极(PPy/ITO)和HTNs-PPy/ITO电极对吡虫啉的测定效果。结果表明:HTNs降低吡咯聚合反应电位差约0.04 V,HTNs-PPy稳定性好且具有优异的电催化效果,吡虫啉在-1.3~0 V之间呈现出明显的氧化还原峰,吡虫啉浓度在0.5~100μmol/L范围内与峰电流呈良好的线性关系,检出限为0.15μmol/L。修饰电极用于西兰花表面农药残留吡虫啉的直接测定,加标回收率在95.7%~105.0%。

The TiO_(2) nano spherical shell with a wall thickness about 10 nm(HTNs)was prepared by hydrothermal template method.Then the copolymer film of HTNs-PPy was prepared by electrochemical polymerization in 0-0.6 V,and the HTNs and pyrrole were cooperated on the surface of ITO electrode to obtain HTNs-PPy/ITO sensor.The effect of polymerization buffer solution pH on the hardness and electrochemical ability of HTNs-PPy was investigated.The surface of HTNs and the sensor were characterized by SEM and TEM.The determination for imidacloprid of the bare ITO,PPy/ITO and proposed HTNs-PPy/ITO sensors were compared,and the results showed that the coupling membrane sensor owns high stability and good catalytic activity for the determination of imidacloprid.The obvious redox peaks for imidacloprid could be observed in the range of-1.3-0 V.The peak current showed a good linear relationship with the concentration of imidacloprid in the range of 0.5-100μmol/L,with the detection limit of 0.15μmol/L.The standard recoveries ranged from 95.7%to 105.0%were obtained in the detection of residual imidacloprid on the surface of broccoli using the proposed HTNs-PPy/ITO sensor.