Semiconductor Nanocrystals-Reduced Graphene Composites for the Electrochemical Detection of Carbendazim

A new nanocomposite based on ZnCdTe semiconductor nanocrystals (NCs) synthesized in situ on reduced graphene oxide (rGO) was obtained. The heterostructure was characterized using UV-Vis emission and absorption spectroscopies, which provided evidences of the growth of the nanocrystals onto the rGO matrix. To evaluate the electrochemical performance, carbon paste electrodes modified with the nanocomposite (QD-rGO/CPE) were prepared, showing high sensitivity in the electroanalytical detection of the pesticide carbendazim. Under optimal operational conditions a calibration curve was constructed with a linear behavior in the range of 9.98 × 10-8 to 1.18 × 10-5 mol L-1, with a correlation coefficient of 0.997. The limit of detection (LOD) and the limit of quantification (LOQ) for carbendazim were 9.16 × 10-8 and 2.78 × 10-7 mol L-1, respectively. The electrode is successfully applied for the determination of carbendazim in orange juice samples.本研究成功制备了一种基于ZnCdTe半导体纳米晶（nanocrystals, NCs）的新型纳米复合材料，该纳米晶原位合成于还原氧化石墨烯（reduced graphene oxide, rGO）表面。采用紫外-可见发射及吸收光谱法对所得异质结构进行表征，结果证实纳米晶成功生长于rGO基体之上。为评估该纳米复合材料的电化学性能，本研究制备了经该纳米复合材料修饰的碳糊电极（QD-rGO/CPE，其中QD为量子点纳米晶），该电极在农药多菌灵的电分析检测中表现出高灵敏度。在最优操作条件下构建校准曲线，其线性范围为9.98×10^-8 至 1.18×10^-5 mol·L^-1，相关系数达0.997。该方法对多菌灵的检出限（limit of detection, LOD）与定量限（limit of quantification, LOQ）分别为9.16×10^-8 mol·L^-1和2.78×10^-7 mol·L^-1。该修饰电极可成功应用于橙汁样品中多菌灵的含量测定。