Study On Detection Of Organophosphorus Pesticides Based On Molecularly Imprinted And Luminol Chemiluminescence System

Organophosphorus pesticides are widely used as insecticides on crops to improve productivity and quality.But the use of large quantities of these compounds will have a negative impact on the environment,which is harmful to human health.Therefore,establishing the method for detecting monocrotophos pesticide residues is very significant.Based on molecular imprinting technique and luminol-hydrogen peroxide chemiluminiscence(CL)system,two methods were established for detecting the residues of organophosphorus pesticide.The main results are as follows:1.The molecularly imprinted polymer(MIP)was synthesized by the bulk polymerization,using monocrotophos,methacrylic acid,and ethylene glycol dimethacrylate as the template molecule,functional monomer,and cross-linker,respectively.Static adsorption,dynamic adsorption and selective experiments showed that the prepared MIP had good selectivity and specific adsorption toward monocrotophos.Using the MIP as identifying material,a new sensor of molecularly imprinted solid-phase extraction coupled with flow-injection chemiluminescence(FICL)for the detection of monocrotophos was fabricated based on the enhancement of CL intensity for monocrotophos in luminol-hydrogen peroxide system in alkaline medium.Results showed that under the optimal conditions,the enhanced CL intensity was linearly proportional to the concentration of monocrotophos range from 0.0023 to 10 mg/L,and the limit of detection of the method was 0.001 mg/L.Rape and pakchoi samples spiked with monocrotophos at three levels were analyzed by the developed method with recoveries between 89.3% and 105.9%.2.Using the synthetic trichlorfon hapten-BSA-luminol as chemiluminescence marker and prepared trichlorfon MIP as biomimetic antibody,a method of flow-injection chemiluminescence biomimetic immunoassay(FICL-BI)toward trichlorfon was developed.Factors that influencing the competitive immune reaction were optimized.Results showed that when hydrogen peroxide concentration was 0.4 mol/L and the competitive reaction was in pH 7.2 PBS solution,the sensitivity of the method(IC50)was 2 mg/L and the limit of detection(LOD,IC15)was 0.0024 mg/L.The recovery rates of spiked carrot and cabbage were ranging from 76.7% to 89.7%.