In Situ SERS Imaging Study Of Pesticide Residues Inside And Outside Vegetable Leaves

Food safety especially pesticide residues in agricultural and sideline products,is an issue that endangers human health.Owing to the high sensitivity,surface enhanced Raman spectroscopy(SERS)technology has a wide range of applications in analysis and detection.With the development of instrument technology,the combination of SERS technology and confocal technology enables complex spectral information data to be visualized in an easy-to-understand color difference spectrum.This has great significance for daily food safety testing.Based on this background,we used SERS imaging technology to detect pesticide residues on and in vegetable leaves and the washing performance of homemade detergents and commercial detergents has been compared by using SERS imaging technology.This method is of great significance for food safety assessment,especially the assessment of chemical constituents in food,to ensure food safty.This method has advantages of high sensitivity,easy to operate,convenient and fast,and can detect or monitor food safety in a real-time,in-situ and non-destructive way.Specifically carried out the following work:(1): The AuNPs@MBA composite nanoparticles with different particle sizes were synthesized by classical methods.The SERS imaging technology was used to study the nanoparticle's permeation behavior with water spinach leaves.And different factors were investigated to obtain the optimal experimental conditions,such as different confocal modes,different sampling modes,etc.(2): In the first work,it was found that the nanoparticles can penetrate into the inside of the leaves.The gold nanoparticles used have little harm to plants,and it is also a good SERS substrate.The representative systemic pesticide thiabendazole and the non-systemic pesticide thiram were selected as pesticide residue samples.It was found that starch paste detergents also have good washing effects,even better than commercial detergents,when washing efficiency of three different ingredients of detergents are compared by SERS imaging.What's more,Z-stack SERS imaging showed that for systemic pesticides pesticide residues were found not only on the surface but also inside the plant leaves.