Preparation Of Composite Fiber Membrane And Its SERS Analysis Of Pesticide Residues

In recent years,food safety has received considerable attention.Surface enhanced Raman scattering（SERS）,as a rapid fingerprint type recognition and non-destructive testing technology,has become a promising technology to meet the growing demand for food safety analysis.At present,the emerging flexible SERS substrates have received great interest as substitutes for colloidal and rigid SERS substrates.Flexible SERS substrates have the advantage of being easy to sample by wrapping or wiping on non-planar surfaces,which helps detect contaminants on food surfaces and provides new clues for non-destructive and sensitive detection of food analytes.Based on the above research background,the main research content of this paper is as follows:In Chapter 2,silver nanowires（AgNWs）with a diameter of approximately 80 nm were prepared using polyol reduction method,and then self-assembled onto the surface of polyvinyl chloride（PVC）films.Due to the large accumulation of AgNWs on the surface of the thin film,they can generate rich"hotspots",forming excellent electromagnetic field enhancement effects and high sensitivity.The feasibility of SERS detection for AgNWs/PVC composite fiber membranes has been improved through experiments such as optimizing PVC content,comparing various conditions of treatment,and exploring repeatability and stability.In the sample detection,thiram（THI）and malachite green（MG）were selected as the detection targets,with repeatability relative standard deviation（RSD）of 10.91%and 10.28%,and correlation coefficients of 0.9482 and 0.9531,respectively.The detection limits of the two samples reached 2.62×10^-11 mol·L^-1 and 7.41×10^-10 mol·L^-1,respectively.In the actual sample detection experiment,THI residues on the surface of fruits and vegetables and MG green residues on the surface of fish were detected,with recovery rates ranging from91.51%-107.34%and 92.32%-106.51%,respectively.The experimental results indicate that AgNWs/PVC composite fiber membrane has certain application potential in food detection.In Chapter 3,gold nanowires（AuNWs）with a diameter of approximately 2 nm were prepared using silane mediated and oleamine reduction methods,and then self-assembled onto the surface of polyvinyl chloride（PVC）films.Ultrathin nanowires can be easily assembled into two-dimensional network structures,which contain a large number of tightly packed parallel nanowires that can adapt to different detection conditions when deposited on a flexible substrate.The feasibility of SERS detection for AuNWs/PVC composite fiber membranes has been improved through experiments such as optimizing PVC content,comparing various conditions of treatment,and exploring repeatability and stability.In the sample detection,methyl parathion（MP）and malachite green（MG）were selected as the detection targets,with repeatability relative standard deviation（RSD）of 12.09%and 10.85%,and correlation coefficients of 0.9773 and 0.9937,respectively.The detection limits of the two samples reached3.34×10^-9 mol·L^-1 and 1.89×10^-8 mol·L^-1,respectively,enhancing hadrons.In the actual sample detection experiment,MP residue on the surface of fruits and vegetables and MG green residue on the surface of fish were detected,with recovery rates ranging from92.83%to 113.03%and 87.91%to 108.13%,respectively.The experimental results indicate that AuNWs/PVC composite fiber membrane has certain application potential in food detection.