Mycotoxins are secondary metabolites that are produced by toxin-producing fungi during production,storage,transportation,and processing of agriculture products.Aflatoxin M1(AFM1),deoxynivalenol(DON)are two common mycotoxins,which AFM1 is mainly found in milk and dairy products,and DON is mainly found in grain,feed and food.Humans and animals may easily cause organ damage,reproductive abnormalities,immunosuppression,and canceration after ingesting agricultural products with excessive mycotoxins.Therefore,it is of great significance to establish a rapid,convenient,sensitive and specific method to detect mycotoxins in agricultural products for the government supervision and protection of consumer safety.This paper established two rapid detection methods based on immunoassay,the main research contents are as follows::(1)Preparation and application of AFM1 electrochemical immunosensor based on graphene oxide-chitosan(GO-CS)/cerium dioxide-chitosan(Ce O2-CS)nanocomposite.First,the prepared GO-CS and Ce O2-CS were modified layer-by-layer on the surfaces of screen-printed electrodes(SPEs)to amplificate their electrochemical signals.The good biochemical properties of graphene oxide(GO)and cerium dioxide(Ce O2)could be used for immobilizing AFM1 monoclonal antibodies on SPEs greatly.The performance of AFM1immunosensor was studied by differential pulse voltammetry(DPV)and cyclic voltammetry(CV).Under optimal conditions,with a good linear relationship of 0.01~1 ng/m L,and detection limit of 0.009 ng/m L.This method had good specificity and high sensitivity.The immunosensor had been used to detect milk samples with spike recovery rate of96.15%~104.25%.(2)Study on time-resolved fluorescence immunochromatographic detection of DON based on Ig G labeling.DON used as the target analyte,and polystyrene fluorescent microspheres used as the labeling material,a secondary antibody-labeled fluorescent probe prepared by coupling with goat anti-mouse Ig G,with the amount of1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride(EDC)and the amount of goat anti-mouse Ig G labeled,spraying amount of immune reagent,the amount of DON monoclonal antibody and other parameters optimized,a resolution fluorescence immunochromatographic detection method had been developed.Because a single-molecule DON monoclonal antibody could bind multiple fluorescent probes,a detection method based on a secondary antibody labeling method could amplify the intensity of the fluorescent signal on a unit antibody and improve detection sensitivity.In methanol solution,corn matrix and feed matrix,the detection sensitivity of this method to DON was 0.121,0.206 and 0.216 ng/m L respectively.The blank corn and feed matrix were spiked.The recovery rate in corn matrix was 88.07%~121.22%with the relative standard deviation lower than 10.49%.The recovery rate in feed matrix was94.8%~107.49%with the relative standard deviation below 8.74%.The detection method was compared with Liquid chromatography tandem mass spectrometry(LC-MS/MS),with the recovery rate of 80.24%~117.4%.The method had high detection sensitivity,good precision and accuracy,good specificity,saved the amount of monoclonal antibody,and could realize the detection of DON in a short time. |