基于二氧化钛/石墨烯纳米复合物的光电化学适体传感器测定土霉素

Determination of Oxytetracycline Using a Photoelectrochemical Aptamer Sensor Based on TiO2/Graphene Nanocomposites

采用水热法在掺杂氟的SnO2(FTO)导电玻璃上生长纳米二氧化钛(TiO2),并通过简单的电化学还原在其表面原位沉积石墨烯,以纳米TiO2/石墨烯为光电传感基底,构建用于土霉素(OTC)检测的光电化学适体传感器。通过扫描电镜表征了复合材料的形貌,电化学工作站测试了单一材料与复合材料的光电响应性能。结果表明,相比于单一的TiO2,TiO2/石墨烯复合材料能明显增强光电流响应,提高灵敏度。基于土霉素适配体对土霉素的高特异性识别,将其固定在TiO2/石墨烯复合纳米材料修饰的FTO表面,可用于土霉素的测定。该方法对目标物的线性范围为5.0×1.0^-9~5.0×10^-6mol/L,相关系数(r)为0.9887,检出限为1.0×1.0^-9mol/L。方法简单、成本低、线性范围宽,有望于实际样品中土霉素残留的测定。

A photoelectrochemical aptamer sensor for the detection of oxytetracycline(OTC)was constructed with nano-TiO2/graphene composites as photoelectric sensor substrate.Firstly,the nano-TiO2 was synthesized by hydrothermal method on the fluorine-doped tin dioxde(FTO)conductive glass.Then the graphene oxide was reduced to graphene by the simple electrochemical method,which was deposited on the surface of TiO2/FTO.The morphology of the obtained TiO2/graphene composites was characterized by scanning electronic microscopy(SEM).The electrochemical working station was applied to measure the photoelectric response.Results showed that the TiO2/graphene composite material could obviously increase the photoelectric current and improve the sensitivity.Based on the fact that the oxytetracycline aptamer could specifically recognize oxytetracycline,it was immobilized on the surface of TiO2/graphene nanocomposite modified FTO electrode for oxytetracycline detection.The method was applied in the detection of oxytetracycline with a linear range of 5.0×1.0^-9-5.0×1.0^-6 mol/L(r=0.988 7)and a detection limit of 1.0×1.0^-9 mol/L.With the advantages of simplicity,low cost and wide linear range,the method is applicable for the determination of oxytetracycline residues in real samples.