Preparation Of Laser Induced Graphene Sensing Electrode And Electroanalysis Of Animal-derived Agro-products In Safety

Graphene(G)materials have received extensive attention from researchers due to their excellent electrical conductivity,excellent electron transfer rate and other properties,and have become a widely used material in the field of electrochemical analysis.However,the traditional preparation method of graphene is complicated and expensive,which severely limits the further application of graphene.Therefore,a new strategy to produce graphene materials quickly,in large quantities and at low cost can effectively solve the existing problems.This thesis will use polyimide(PI)film as the substrate,based on laser direct writing technology,a one-step method to quickly prepare laser-induced graphene(LIG),and through the modification and modification of LIG electrode materials,three different flexible sensors,LIG,Pt-LIG and PEDOTLIG were constructed.Safety analysis of fish freshness,clenbuterol and carbendazim in animal-derived agricultural products.The main contents are as follows:(1)Preparation of LIG flexible electrode and its evaluation of fish freshness:A flexible 3D porous graphene nanoenzyme electrode was prepared on polyimide by laser direct writing technology,which is an economical,efficient and rapid one-step preparation method.The morphology,structure and performance of the prepared LIG flexible electrode were characterized and tested.LIG has excellent mechanical flexibility,unique 3D porous structure,expected cycle stability and high conductivity,and a new type of electrochemical nano-sensing platform has been constructed.Through electrochemical detection of xanthine(XT)and hypoxanthine(HX)and combined with artificial neural network(ANN)algorithm-based machine learning(ML),the intelligent evaluation of fish freshness has been successfully realized.The prepared LIG electrode showed special nanoenzyme charactristic in electrochemical detection of XT(0.3-179.9 ?M)and HX(0.3-159.9 ?M),and the limit of detection(LOD)was 0.26 ?M and 0.18 ?M,respectively.In addition,voltammetry is used to detect the contents of XT and HX in fish at different storage times,and an ML model is established based on the ANN algorithm to realize intelligent analysis and evaluation of fish freshness.(2)Preparation of Pt-LIG flexible electrode and its detection of clenbuterol:Using laser direct writing technology,a 3D porous LIG electrode was one step prepared on the PI film,and the LIG electrode was modified by chemical method,using sodium borohydride as a reducing agent to reduce chloroplatinic acid,Pt nanoparticles were loaded on the surface of the LIG electrode,and Pt-LIG composite electrode material was prepared.Compared with LIG electrode,Pt-LIG electrode has high conductivity,larger surface area and better electrocatalytic ability.It is used as a new type of electrochemical sensing platform for electrochemical detection of clenbuterol(CLB),and a wide detection linear range of 0.1 – 820.9 ?M is obtained,the lower LOD is 0.072?M,CLB in the actual sample of beef was detected,and an effective and acceptable recovery rate was obtained.(3)Preparation of PEDOT-LIG flexible electrode and its detection of carbendazim: Using laser direct writing technology,LIG electrode was prepared on PI film by one-step method,and the LIG electrode was modified by electrochemical deposition of EDOT.The 0.01 M EDOT monomer was CV deposited in 0.01 M lithium perchlorate acetonitrile solution to prepare the PEDOT-LIG composite electrode material.Compared with LIG electrode,PEDOT-LIG electrode has higher conductivity,larger surface area and better electrocatalytic ability.It is used as a new type of electrochemical sensing platform for the electrochemical detection of the pesticide carbendazim(CBZ).Its detection linear range is 0.09 – 19.99 ?M,and the LOD is 0.035?M.It has a lower LOD,higher sensitivity and good practicability.It also successfully realizes the sensitive detection of CBZ with a LOD of 0.065 ?M on wireless portable sensor.In this paper,we successfully proposed a new strategy for preparing graphene materials quickly,in large quantities and at low cost.Through laser direct writing technology,we successfully prepared laser-induced graphene LIG,and prepared LIG into flexible electrode.In addition,we also prepared Pt-LIG and PEDOT-LIG composite electrode materials by surface modification of electrode materials.Different electrochemical sensors were constructed by the electrodes prepared,which realized the rapid and sensitive detection of XT and HX in fish,CLB in beef and CBZ in feed.At the same time,the successful detection of CBZ on wireless portable sensors provides a new method for rapid outdoor detection,and lays a certain foundation for the research in the field of wireless intelligent sensors.