Preparation Of The Silicon-based Fluorescent Surface Imprinted Composite Materials And Research On Target Detection Of Pyrethroids In The Environment

In industry and aquaculture,Pyrethroid pesticides（Pyrethroid pesticides,PPs）are used largely which have led residuein water exceeding bid badly,harming to health of human and ecological balance.It indicates that while PPs are used to control pests,it also produces toxic effects on non-target organisms,such as fish,shrimp,crab and even honeybee.A part of trace PPs can affect humen nervous system and reproductive system.In allusion to residual problem of the trace PPs in the complex environment,exploring a new fast and sensitive detection method has been now urgent priority.In this study,it establishes a new fluorescence analytical technique which has excellent selectivity and recognition for specific target molecules with fluorescence detection technology coupling with molecular imprinting technique.Fluorescent dyes are chosen as fluorophore which has narrow emission spectrum and high fluorescent quantum yield.Inorganic nanoparticles are used as carrier,then a molecularly imprinted layer is polymerized on the surface of carrier.It establishes a fluorescence molecularly imprinted composite material,which have fast and efficient,selective and sensitive detection properties,to selectively recognize three kinds of PPs（λ-cyhalothrin,beta-cyfluthrin,fluvalinate）.The main work was as following:（1）A fluorescence molecularly imprinted composite material was designed and synthesized via precipitation polymerization to selectively detect trace LC in the environment.In this study,submicrometer SiO₂ particle was chosen as carrier.Then,fluorescent monomer FITC was modified on the surface of SiO₂ particle with APTS.SiO₂@FITC-APTS@MIPs were prepared,which template molecule（LC）,functional monomer（AM）,cross-linking agent（DVB）,initiator（AIBN）were added,respectively.The material was characterized by Fourier transform infrared（FT-IR）,Thermo-gravimetric apparatus（TGA）,scanning electron microscopy（SEM）,and transmission electron microscopy（TEM）.The results show the fluorescent microsphere had core-shell Structure（layer about 100 nm）.The linear relation was setting up between fluorescence intensity（F）and LC concentration（C）,described by Stern-Volmer equation is F0/F-1=0.0162C+0.0272,and LOD is 9.17 nM.（2）The fluorescent molecularly imprinted composite materials were synthesized via precipitation polymerization,which used SiO₂-KH570 as carrier,then template molecules（BC）,fluorescence functional monomer（AF）,crosslinking agent（TRIM）and initiator（AIBN）were added in the heat condition.The composite materials were used to selectively detect the trace BC in the agricultural products.The material was characterized by FT-IR,SEM,and TEM.It indicated that the fluorescent molecularly imprinted composite materials have excellent monodispersity and thin molecularly imprinted polymer layer（about 50 nm）.The composite materials have excellent selective recognition ability,and linear relation in the range of 10.11-80 nM concentration.The linear equation described by Stern-Volmer equation is F0/F-1=0.0213C+0.0859,R2 =0.9919,LOD=10.11 nM.（3）A SiO₂-KH570@FL-FMIPs composite material is fabricated via surface molecular imprinting technique for detection of trace FL in environmental water sample on the suface of SiO₂-KH570 nanoparticle,template molecules（FL）,fluorescent monomer（AF）,cross-linking agent（TRIM）and initiator（AIBN）were added into the reaction system.The characterization indicated it had better monodispersity,stability and fluorescence characteristic.The fluorescence detection experiments showed fluorescence intensity [F] and concentration [C] had good linear relation in the range of 12.145-120 nM.The linear range described by Stern-Volmer equation is F0/F-1=0.0164C-0.0067,correlation coefficient was 0.9975,LOD=12.145 nM.