Preparation Of Metal Nanocomposites And Its Application In SERS Detection Of Pesticide And Veterinary Drug Residues

Surface enhanced Raman spectroscopy（SERS）,as a rapid-response,non-destructive,real-time,and ultra-sensitive detection method,can reflect the chemical structure and composition of molecules to be measured,showing a great application potential in the field of food safety detection.In this paper,the pesticides methyl parathion（MP）,carbaryl（CBL）and the veterinary drug amantadine（AMD）were taken as research objects,two novel SERS detection strategies based on noble metal nanoparticles and metal organic framework（MOF）were constructed for different food substrates.The main works in this study are summarized as follows:（1）A core-shell AuNRs@Ag-enhanced and magnetic separation-assisted SERS immunosensor was developed for rapid,sensitive and specific detection of banned veterinary drug AMD in animal-derived food.This SERS immunosensor works in a competitive strategy,which used 4-mercaptobenzoic acid（4-MBA）labeled AuNRs@Ag with AMD-BSA immobilized as signal probes(AuNRs^4-MBA@Ag-AMD-BSA),and magnetic beads（MBs）with monoclonal antibody（m Abs）covalently attached as capture probes（MBs-m Abs）.Through the competitive binding of the target and the signal probe to the capture probe,the indirect detection of antiviral drug AMD was realized.This detection strategy can detect AMD accurately and sensitively within 30 min with LOD of 0.0038μg/L.The recovery of AMD in animal-derived food（chicken,egg,milk）ranged from 82.0to 106.0%at three added concentrations（0.5,5,50μg/kg）.These results demonstrated that the proposed SERS immunosensing strategy was fast,sensitive and reliable in the quantitative analysis of AMD and can be applied as an effective tool for rapid screening of AMD-contaminated foods.（2）By in situ growth of ZIF-8（MOF）on the surface of Ag nanowires（AgNWs）,a novel bead-string like AgNWs@ZIF-8 core-shell nanochains was controllably prepared and utilized as SERS substrate for in-situ and simultaneous detection of multiple pesticide residues on fruits and vegetables.Due to the microporous structure of the ZIF-8 shell and the SPR properties of the inner AgNWs,the AgNWs@ZIF-8 core-shell nanochains exhibited good adsorption performance and remarkable SERS activity.The SERS detection strategy developed based on AgNWs@ZIF-8 was used for the detection of MP and CBL pesticides,which not only had low LODs(MP:7.6×10^-9mol/L;CBL:5.7×10^-9mol/L),but realized in-situ and simultaneous detection of two kinds of mixed pesticides on fruit and vegetable surface with different roughness,and the recovery rate was 77.4-117.5%.This study demonstrates the application prospect of the SERS detection strategy based on AgNWs@ZIF-8 in pesticide multi-residue detection,and also provides a new idea for the design of novel metal nanoparticle@MOF composites and the in-situ detection of multi-pesticide residues.