磁分离/自清洁复合型单分散微球SERS基底对农药残留的高效检测

Residual pesticides in water have threatened food safety and human health seriously, but conventional detection methods including chromatogram and mass spectrograph are usually time-consuming and couldn't realize rapid-detection. The present technique based on surface-enhanced Raman scattering (SERS) effect of noble metal nanostructures can be used for highly sensitive identification of organic molecules, including pesticides. However, the current SERS-based techniques have encountered difficulties of effective concentration (enrichment), rapid-detection and recyclability of the SERS substrates. In this project we will aim at exploring the composite SERS substrates with multi-functions of magnetic separation, photocatalysis for self-cleaning, surface modification for effective capture of pesticides and single-particle observation for SERS-detection. We will design and build monodispersed composite microspheres with superparamagnetic-inner-core/photocatalysis-middle-shell/noble-metal-nanostructured-outer-shell, which may realize fast concentration, rapid detection of trace pesticide and the reusability of the SERS substrate. We will focus on the relationship between the structural parameters of the composite microspheres and enhanced Raman signals, and the Raman signal enhanced mechanism. The results will lay the foundation for low-cost and effective SERS-based rapid detection of trace pesticides in water, and therefore will be very important to the ecology environment and human health.

农药（除草剂和杀虫剂）在水中的残留严重威胁食品安全和人类健康，传统的实验室色/质谱等方法对农残的检测过程繁琐、耗时，难以实现快速检测。基于贵金属纳米结构的表面增强拉曼散射（SERS）效应，能够高灵敏度的检测与准确识别有机分子。本项目拟基于SERS效应的优势，以水中农残的高效检测为目标，围绕目前SERS基底用于农残检测时急需解决的问题：高效富集、快速检测及基底的循环利用等，研发具有高效富集、分离、高灵敏检测和循环再利用等多功能复合的SERS基底。拟结合磁分离、光催化自清洁、表面修饰富集、单颗粒探测等技术，构筑具有超顺磁内核/光催化中间层/贵金属外壳层组成的单分散复合微球SERS基底，实现对水中农残的快速富集、高效检测及基底的循环利用；研究复合微球的结构参数对农药分子拉曼信号增强的规律与机理；为基于多功能微球SERS基底对水中痕量农残的低成本、高效快速检测提供科学依据，对环境健康具有重要意义。

农药残留在水中的残留严重威胁食品安全和人类健康，传统的色/质谱等方法对农残的检测过程繁琐、耗时，难以实现快速检测，开发具有高效富集、分离、高灵敏检测和循环再利用等多功能复合的SERS基底对农药残留的快速检测具有重要意义。在本项目支持下，研究团队首先制备了单分散超顺磁四氧化三铁微球，然后以磁性微球为模板，开发了多种壳层沉积方法如凝胶限域法和模板激活策略，实现了单分散磁基多功能复合微球SERS基底的控制合成，在此基础上提出了磁诱导单分散磁基多功能复合微球组装均匀薄膜SERS基底的新方法，实现了微球型SERS基底高灵敏度的优势与阵列薄膜型SERS基底信号重复性优势的完美结合，初步研究表明这种微球阵列SERS基底能够对水体中农残分子秋兰姆进行重复性高灵敏度探测。在此基础上，进一步构筑了用于自清洁的光催化壳层，初步实现了SERS基底的重复利用。我们提出的磁诱导单分散磁基贵金属复合微球构筑均匀薄膜SERS基底的方法，综合了磁性分离、贵金属壳层微纳结构和微球阵列组装等技术，将微球型SERS基底和有序薄膜SERS基底的优势结合起来，对SERS检测研究领域具有重要的科学意义和应用价值。