Research On Rapid Detection Technology Of Pesticide Residues On Paper-based Surface Enhanced Raman Spectroscopy

In modern agriculture,the excessive use and unreasonable use of pesticide chemicals have caused serious environmental and food safety problems.Pesticide residues with greater toxicity have greatly affected the environment and human health.However,traditional detection methods still have the disadvantages of long detection time,complex sample preparation,expensive equipment,and complicated instrument operation,which cannot meet the needs of rapid detection of pesticide residues.In order to achieve rapid detection of pesticide residues and minimize the harm of pesticide residues,this paper has developed a pesticide residue detection method based on spectral detection technology.This detection method is short in time,simple in operation,and low in running cost.In this paper,two paper surface-enhanced Raman(SERS)detection substrates that can be used to detect multiple pesticide targets were prepared.These are filter paper SERS detection substrate and paper microfluidic separation channel detection substrate.In this paper,first,chlorpyrifos,deltamethrin,and atrazine were used as single pesticide targets,and a mixture of chlorpyrifos,deltamethrin,and atrazine are used as mixed pesticide targets.The performance of the SERS detection substrate for detecting target pesticides was systematically evaluated.The linear relationship,linear range,and detection limit between the detection signal intensity and concentration of the detection substrate for different target samples were determined.Secondly,this article used a mixture of dimethoate and thiuram as the target to complete its separation and SERS detection research in the paper microfluidic separation channel detection substrate.The influences of injection volume,mixed sample concentration ratio,channel width on the diffusion distance of the target in the paper microfluidic separation channel were investigated,and the optimal detection conditions of the two targets in the mixed sample were determined.Finally,Finally,in this paper,the kinetics of photocatalytic degradation of the target by paper SERS detection substrate was studied,and the degradation and removal performance of the detection substrate on different target samples was completed,and the cycle detection performance of the detection substrate was investigated.Through the surface water standardization experiment,the detection performance of the detection substrate on the target pesticide in the actual water sample was investigated.The resulted show that the prepared paper Raman detection substrate could realize the qualitative and quantitative analysis of five samples,and it could meet the requirements of the quality standards for pesticides in the groundwater environmental quality standards(GB14848-2017)and surface water environmental quality standards(GB3838-200).The paper SERS substrate can be degraded to remove the target pesticide after being irradiated by UV light for 10 minutes,and the detection result of the substrate used for 5 times remained stable.The optimal detection conditions for the mixed samples of dimethoate and thiuram in the paper microfluidic separation channel were 100 ?L injection volume,1 mm channel width,and the concentration ratio(thiuram/dimethoate)was greater than 0.8 or less than 0.6.The diffusion distance of 500ppb thiuram was 1.8cm,and the diffusion distance of 500ppb dimethoate was 2.2cm.The paper microfluidic separation channel could achieve the degradation and removal of the target after the detection substrate was illuminated.The substrate remained stable after 5 times of recycling detection.The diffusion distance of thiuram was 1.8 cm,and the diffusion distance of dimethoate was 2.2 cm.The paper microfluidic separation channel could achieve the degradation and removal of the target after the detection substrate is illuminated.The substrate remains stable after 5 times of recycling detection.This work applied filter paper materials to the preparation of surface-enhanced Raman detection substrates.This work combined surface-enhanced Raman detection technology with paper microfluidic channel technology for the separation and detection of multiple pesticide targets in complex samples.This detection method achieved the simultaneous and fast detection of multiple pesticide targets.At the same time,this experiment combines photocatalysis technology with SERS detection technology.The paper SERS detection substrate prepared in this experiment has a photocatalytic function.