Molecular Imprinting For Surface-enhanced Raman Spectroscopy Application In The Detection Of Endosulfan

Organochloro Pesticides?OCPs?is a class of chlorinated organic pesticides,which has strong toxicity,carcinogenicity and teratogenicity.Due to the food chain and the biological cumulative effect,OCPs brings great harm to the ecological environment and human health.Currently the widely used detection methods of OCPs have high sensitivity,but they are expensive,operation-complicated,time-consuming,and without real-time in situ monitoring.Surface-Enhanced Raman Scattering spectroscopy?SERS?is a kind of optical enhancement phenomenon of nanoscale rough surface or particle system.With the advantages of rich information content,high sensitivity,less-sample pretreatment and operating easily,SERS is considered to be a very promising analytical technique.And the molecular imprinting?MIP?is known as a technique for creation of tailor-made binding sites with memory of the shape,size,and functional groups of the template molecules,which is always used as selective adsorbents.With the marriage of MIP and SERS,it is expected to achieve real-time,seletive,and rapid detection of OCPs.This thesis is focused on the appliction of MIP in SERS detection of Endosulfan,one of OCPs.The main research work is described as follows:1.Au nanoparticle SERS detection of Organochloro Pesticides based on the interaction between Cl and Au.The endosulfan,a kind of OCPs,was set as an example.After interacting with Au nanoparticle,both changes of UV-visible absorption and characterizations of SEM showed that there exists the interaction between endosulfan and Au nanoparticle.Furthermore,the interaction between Cl atom of endosulfan and Au is verified through the FT-IR and Raman spectroscopy.And the interaction facilitated the approach of endosulfan to the surface of Au nanoparticle,which made the SERS detection success.The limit detection is 10^-12M.We also applied the method to another kind of OCPs,chlordane,successfully.2.Preparation and characterization of Au@MIP core-shell nanoparticles.Through changing the monomer and cross-linker,we prepared the Au@MIP core-shell nanoparticles with visible shell under the TEM.The nanoparticles mainly contained four elements C,O,Cl and Au by Energy Dispersive Spectrometer analysis.And the Au@MIP core-shell nanoparticles showed the same FT-IR spectrum with MIP;Application of substrate made of Au@MIP core-shell nanoparticles in the SERS detection of OCPs.Due to the specific recognition sites of shell,the templates can be selectively held in the shell part,then reached the surface of Au nanoparticle through the so-called“gate”effect,which made the SERS work.At the same time,we have demonstrated that the SERS substrate has excellent selectivity,reproducibility and stability.