多菌灵分子印迹比率型荧光传感器的构建及其特异性可视化检测机理

Carbendazim is widely used in China, some countries have banned the use of it because of its suspected health risk, the MRLs of the international standard are becoming more and more stringent. As a result, developing simple, sensitive and highly selective analytical methods for Carbendazim detection is of great importance in food safety and international trade. Application of high sensitivity of fluorescent sensor and high selectivity of molecularly imprinted polymers, the ratio of fluorescence intensity of quantum dots with different wavelength was changed after the binding of Carbendazim to the sensor, which lead to solution with distinct colour changes, the visual detection method of Carbendazim will be developed. Firstly, two CdTe quantum dots with different fluorescent emission wavelength has been prepared, molecularly imprinted ratiometric fluorescence sensor will be synthesized via quantum dots modification and precipitation polymerization. Secondly, the performance and the mechanism of fluorescence, selective recognition and visual detection will be discussed. Finally, the effect of visual detection method will be verified. The sensor will be constructed with application of molecular imprinting and ratio-dependent fluorescent, the mechanisms of specific visual recognition will be clarified, and the sensor can be applied to the simple, sensitive, specific and visual detection of carbendazim in environmental and agricultural products, which will be an innovative research method for analysis of pesticide residues, and has important scientific significance and application value.

多菌灵是我国广泛使用的杀菌剂，因怀疑其有健康风险，部分国家已禁止使用，其国际残留限量标准也越来越严格。因此，建立简单、灵敏及选择性高的分析方法对农产品安全及国际贸易有重要意义。本研究拟利用分子印迹的高选择性和比率荧光的高灵敏性，多菌灵与印迹层结合后导致不同波长量子点荧光强度比值发生变化，进而导致检测溶液颜色发生变化，实现多菌灵的可视化检测。研究以前期制备的不同波长CdTe量子点为材料，通过量子点修饰和沉淀聚合反应制备分子印迹聚合物，构建多菌灵分子印迹比率型荧光传感器，优化并明确传感器选择性及可视化检测性能，阐明其特异性识别与可视化检测机理，验证传感器对多菌灵的检测效果。研究将利用分子印迹和比率荧光技术构建传感器，阐明其特异性识别与可视化检测机理，解决环境和农产品中多菌灵的简单、灵敏、特异性与可视化检测问题，为农药残留分析开创新的研究思路，有着重要的科学意义与应用价值。

多菌灵残留是影响我国农产品质量安全的重要指标，简单、灵敏及特异性高的分析方法是有效检测和监管多菌灵残留的重要技术手段。本项目以前期制备的不同波长CdTe量子点为材料，通过量子点修饰和沉淀聚合反应制备分子印迹聚合物，构建了多菌灵分子印迹比率型荧光传感器，优化并明确了传感器选择性及可视化检测性能，阐明了其特异性识别与可视化检测机理，验证了传感器对多菌灵的检测效果，并应用到环境水和农产品中多菌灵的检测中。.通过量子点修饰和沉淀聚合反应，制备的荧光传感器的分子印迹结构能特异性识别多菌灵分子，且核壳结构中红色和绿色量子点提供了比率荧光检测信号。在传感器浓度为250 mg/L、检测时间10 min，pH = 7的最优检测条件下，多菌灵的浓度和传感器荧光强度比值之间存在良好的线性关系，线性方程为C = 6.38 + (96.85 - 6.38)/(1 + (F1/F2)/(F1/F2)0)^1.09)，相关系数R2 = 0.9569。根据线性方程得到传感器的检测限（LOD、EC20）为0.074 mg/L，线性范围（EC20-80）为0.074 - 0.94 mg/L。传感器的荧光颜色随着多菌灵浓度的变化而发生明显变化，逐渐由黄绿色加深到红色。将构建的传感器用于河水、大米等实际样品的检测，平均添加回收率在77.21 - 107.63%之间，变异系数在0.25 - 6.58%之间，表明构建的比率型荧光传感器对多菌灵检测具有较好的准确度。分子印迹识别位点是传感器能够特异性结合多菌灵的关键，而传感器结合多菌灵后导致核壳结构不同部位量子点荧光强度比值发生变化，实现了多菌灵的可视化检测。.研究利用分子印迹的高选择性和比率荧光的高灵敏性，构建了多菌灵分子印迹比率型荧光传感器，实现了环境和农产品中多菌灵简单、灵敏、特异性与可视化检测。研究结果为农产品质量安全检测提供了技术支撑，也为其他农药残留检测析方法的建立提供了重要借鉴。