基于多点相互作用的手性农药分子识别及其食品残留分析研究

It is of great significance to determine the enantiomeric composition of chiral pesticide in environmental media for the regulating the use of pesticides and food safety. In the present project, the chiral discrimination of chiralpesticides in cyclodextrin system will be carried out, which is based on the interaction difference between the enantiomers of chiralpesticides and the micro-environment around them. On this basis, the multi-sites interaction micro-environmental system will be fabricated after adding the appropriate chiral additices. This may result to enlarge the difference between the enantiomers of chiralpesticides and the micro-environment and improve the molecular recognition function of chiral pesticide. Then the chiral phosphorescence probe will be designed and synthesized and the chiral discrimination of pesticides contained bromine atom will be achieved based on the heavy atom perturbation of bromine. At the same time, chiral discrimination mechanism will be further explored with the help of the nuclear magnetic resonance, infrared spectrum, circular dichroism and so on., and the multi-sites interaction model will also be establised combied with the molecular mechanics calculation technology. Finally, the enantiomeric composition of chiral pesticide will be determined based on the proposed phosphorescence method and applied to the chiral pesticide residue analysis in apple, grapes. It will provide new method for the chiral pesticide residue, but also play a significant role in the people's food security early warning information. This present study will further enrich the current analysis techniques of pesticide residue, and can be also applied in the monitoring other chiral pesticides.

对映体水平上测定环境介质中手性农药对于进一步规范农药使用与人们饮食安全意义重大。本项目以几类重要的手性农药分子为研究对象，基于其在环糊精手性微环境体系中的发光特性差异，实现手性农药分子识别功能，并通过引入适当的手性添加剂，构筑有效的分子多位点识别微环境，进一步扩大分子间相互作用差异，提高手性农药分子的识别功能。同时，设计制备高效的手性微环境磷光探针，利用溴原子的重原子微扰作用，实现含溴类手性农药对映异构体的分子识别。并借助核磁共振、红外、圆二色谱等技术，进一步探索手性识别机理，结合分子力学计算建立手性分子多点识别作用模型。最后，建立测定手性农药对映异构体组分的磷光分析法，并将其用于苹果、葡萄、大豆等食品中手性农药残留分析，为手性农药残留分析提供新方法，并为人民饮食安全提供重要的预警信息。此研究将进一步充实现有的农药残留分析技术，并可拓展到其他手性农药分子的定量研究和信息获取。

作为荧光法的姊妹技术，室温磷光法具有较小的光谱干扰、较长的发射波长，较大的Stokes 位移及较长的磷光寿命等特性，在手性农药分子识别中发挥着重要作用。本项目利用环糊精分子的内在手性特性，通过构筑有效的多点分子识别微环境体系，实现了咪唑喹啉酸对映异构体的手性分子识别功能。同时，将发光分子萘普生桥联至环糊精分子上，制备了磷光探针，实现了二溴甲烷的选择性检测及丙溴磷对映异构体分子的手性识别功能，并对其食品残留进行了分析检测。得出了重要结论：.（1）环糊精的疏水空腔不仅可为咪唑喹啉酸提供保护性介质，更可为其对映异构体分子提供分子识别的手性空腔。咪唑喹啉酸对映异构体在beta-环糊精/1,2-二溴乙烷体系中可以发射较强的磷光，它们的寿命差异可达30%以上，从而可以实现咪唑喹啉酸对映异构体的手性识别。.（2）S-(-)-萘普生-beta-环糊精磷光能发射较弱的室温磷光，二溴甲烷存在时可以大大增强其磷光发射，这是由于二溴甲烷能与S-(-)-萘普生-beta-环糊精形成共包合物，减少了溶剂分子对发光体S-(-)-萘普生的碰撞猝灭，同时，二溴甲烷还进一步增强了其三线态的跃迁。基于此，实现了二溴甲烷的室温磷光识别检测，大大提高了其检测的便捷性。.（3）丙溴磷可以增强S-(-)-萘普生-gamma-环糊精的室温磷光，同时，研究发现R-丙溴磷能引起S-(-)-萘普生-gamma-环糊精磷光较大的变化，此外，R-丙溴磷引起体系圆二色谱较大的变化，从而实现了环糊精体系中丙溴磷对映异构体的手性识别功能，建立了测定丙溴磷的室温磷光法，并对其食品残留进行了分析检测。