Development Of Mycotoxin Quantum Dots Fluorescence Immunochromatographic Test Strips

The contamination of mycotoxins is widespread in cereals and other foods,which has a serious impact on the nutritional value and safety of cereals and their products.At present,the detection methods of mycotoxins mainly include thin layer chromatography,high performance liquid chromatography,liquid phase Chromatography-tandem mass spectrometry,enzyme-linked immunosorbent assay,immunochromatography,and the like.Among them,immunochromatography has the advantages of being simple and quicker than other methods,and is more suitable for on-site high-efficiency and sensitive large-scale detection.In order to improve the safety of cereals,a single-component and multi-component quantum dot fluorescence immunochromatography was established for the most harmful ochratoxin A(OTA)and aflatoxin B1(AFB1)in mycotoxins.Rapid test method for test strips,including rapid detection method for detecting quantum dot fluorescent immunochromatographic test strips of OTA,detecting rapid detection method of AFB1 quantum dot fluorescence quenching immunochromatographic test strip,and simultaneously rapid detection method for detecting quantum dots fluorescent quenching immunochromatographic test strips of OTA and AFB1.OTA and AFBi rabbit serum were purified by Protein A-Sepharose 4B purification column to prepare polyclonal antibodies with concentration of 1.4 mg/mL and 2.0 mg/mL respectively.Chicken ovalbumin(OVA)and OTA were respectively activated by activated ester method.The hapten and the AFB1 hapten are coupled to obtain the corresponding antigen;QDs-Ab and QDs-OVA are prepared by covalently bonding quantum dots(QDs)with OTA antibody and OVA,respectively;colloidal gold is obtained by physical adsorption.(AuNPs)and antibody(Ab)were separately ligated to prepare AuNPs-Ab.By optimizing the concentration of the C-line and T-line coating materials of the test strip,the type of the sample diluent,the type of the nitrocellulose membrane,the amount of the signal probe,and the amount of the working fluid,respectively,under the optimal reaction conditions,The detection limit of OTA quantum dot-labeled immunochromatographic test strips in sample dilutions is 0.5 ?g/L,and the detection limit in corn,rice,barley and oat samples is 5 ?g/kg;The detection limit of OTA quantum dot fluorescence quenching immunoassay strip test method is 0.1 ?g/L in the sample diluent,and the detection limit is 1?g/kg in the corn,rice,barley and oat samples;The detection limit of AFBi quantum dot fluorescence quenching immunoassay strip test method was 0.2 ?g/L in the sample diluent and 2 ?g/kg in the corn,rice,barley and oat samples.Based on the one-component detection of OTA and AFB1,based on the optimal reaction conditions,the detection methods of OTA and AFB1 multi-residue quantum dot fluorescence quenching immunochromatographic test strips were established,and the detection limits of OTA and AFB1 in the sample dilution were established.The detection limits of OTA and AFB1 in the sample diluent were 0.1 ?g/L and 0.2 ?g/L,respectively,and in corn,rice,barley,oat samples,were 1.5 ?g/kg and 3 ?g/kg,respectively.The test strip detection method has good specificity by cross-reaction,and the accuracy of the OTA quantum dot fluorescence immunochromatographic test strip detection method was verified by commercial kit.It passed the high.performance liquid chromatography-column before GB 5009.22-2016.The derivatization method verified the accuracy of the AFB1 quantum dot fluorescence quenching immunochromatographic test strip.