Fluorescence Immunoassay For Multi-reisdue Detection Of Organophosphorus Pesticides Based On Quantum Dots

In recent years,the quality and safety of agricultural products has been given a lot of attention worldwide,and they have gradually become an important hot spot in the owrld.In order to regulate the rational use of pesticides,more and more countries have established corresponding pesticide residue standards.Due to the low pesticide content,in order to achieve the purpose of quantitative analysis and quantitative analysis of trace pesticides,it is necessary to effectively establish pesticide residue detection methods,especially sensitive,accurate and fast detection methods to protect the ecological environment and consumption.In this study,fluorescent quantum dot-labeled antibodies were used to provide fluorescent detecting signals,and a fluorescence immunoassay method was developed for the detection of single residues of triazophos pesticides and multi-residues of pesticides such as triazophos,parathion,and chlorpyrifos.The main contents are as follows:fluorescent quantum dot modified with carboxyl group,with uniform particle size and excitation wavelength was used.The pesticide monoclonal antibody and the fluorescent quantum dot are coupled,and the coupling agent concentration,reaction time,reaction temperature and the like in the labeling process are optimized to obtain an antibody fluorescent probe labeled with a fluorescent quantum dot.A fluorescence immunoassay method based on fluorescent quantum dots for triazophos pesticides was established.We have optimized theanalytical conditions of the method,which including the working concentration of probe and hapten,as well as working temperature.The method has a good linear relationship in the range of 0.01-25 ?g L-1 with a detection limit of 5 ng L-1.The water,pear,cucumber,rice and apple substrates were added and recovered by the method.The average recovery was 85.0%?110.3%,and the relative standard deviation was 9.4%?17.4%.The method was compared by liquid chromatography and verification by LC-MS/MS.The results show that the method has high accuracy,high sensitivity and reliable results,which can meet the requirements of the analysis of triazophos residues in the actual sample.Based on the analysis method of triazophos pesticides,a multi-residue fluorescent immunoassay method for triazophos,parathion and chlorpyrifos pesticides based on fluorescent quantum dots was established.The fluorescent quantum dot-labeled antibody with emission wavelengths at 520 nm,570 nm,and 630 nm was selected,and the working concentrations of parathion,chlorpyrifos probe and its hapten were further optimized.The results showed that the specificity between the three probes and the three coating haptens was good.Triazophos,parathion and chlorpyrifos are 0.01-25 ?g L-1,0.01-100 ?g L-1,0.01-100.respectively.The linear relationship was good in the range of ?gL-1.and the detection limits were 0.55 ng L-1,1.43 ng L-1 and 1.89 ng L-1.Addition recovery tests were carried out in tap water,rice,cucumber,pear and apple bases and confirmed by LC-MS/MS.The average recovery rate is 75.7%-113.8%.The relative standardization adjustment is 6.3%-18.2%which is close to the LC-MS/MS results,indicating that the method is sensitive,accurate and reliable,and can meet the requirements of multiple residue analysis of triazophos,parathion and chlorpyrifos in agricultural products.It provides a reference for the analysis of various residues of small molecule chemical pollutants.