Study On Detection Methods For Pesticide Of Carbaryl Based On Immune Magnetic Beads And Molecular Imprinting Technique

Carbaryl is one of the carbamate pesticides, widely used in the prevention and control of pests in wheat, rice, cotton, vegetables, fruit trees, etc. Through inhibiting the activity of cholinesterase and accumulating acetylcholine in the organization, the normal secretion of pests was interfered by carbaryl which belongs to middle and low toxicity pesticides, having a threat to life with acute toxicity, immunotoxicity, reproductive toxicity. Therefore, the detection of carbaryl is of great significance.Pesticide residue is one of the key tests on food safety. The main detection methods of pesticide residue were instrument tests which has high sensitivity, good reproducibility, wide applicable range and multi residues analysis simultaneously. However the instrument tests need complicated sample preparation process, higher testing conditions, longer testing time and professional operation. The circulation of food from field to fork were quick and vast, the instrument tests were difficult to achieve the purpose of rapid detection. Strengthen the research of new method for rapid detection of pesticide residue and development convenient, fast and operability method is preferred.This paper based on immune magnetic beads and molecular imprinting technology, setting up three methods for rapid detection of carbaryl. Main conclusions are as follows:(1) The carbaryl hapten was synthesized and coupled with bovine serum albumin to form complete antigen, getting polyclonal antibody of carbaryl by immune the New Zealand big-eared white rabbit through back subcutaneous multipoint injection. At the same time adopt one-step hydrothermal method to synthetic Fe3O4 magnetic nanoparticles which has amino functional groups. The amination Fe3O4 magnetic nanoparticles integrate with antibody by glutaraldehyde as a capture device and the antigen labeled by horseradish peroxidase as signal amplifier, achieving the purpose of quantitative detection of carbaryl through direct competition. Under optimum conditions, the methods of immune magnetic beads exhibited a linear relation in the range of 1×10-3-10 mg L-1, with a correlation of R2=0.994, inhibition rate can reach 90.6%, the half inhibitory concentration (IC50) was 0.077 mg L-1 and the detection limit (IC15) was 1.48×10-3 mg L-1. The precision for three replicate detections of carbaryl (1mg L-1) was 1.67% (relative standard deviation). Through a series of analysis, we think the method of immune magnetic beads based on antibody can be used for rapid detection of carbaryl.(2) With paper as carrier, carbaryl as template, methacrylic acid as functional monomer, ethylene glycol dimethyl acrylate as the crosslinking agent,2,2’ azodiisobutyronitrile as initiator, synthetic molecular imprinting polymers on the surface of paper through traditional thermal polymerization to get carbaryl molecular imprinted biomimetic antibody, establishing biomimetic enzyme-linked immunosorbent assay and achieving the purpose of the qualitative and quantitative detection of carbaryl by colorimetric determination and reader through direct competition, respectively. Under optimum conditions, The methods of biomimetic enzyme-linked immunosorbent assay by paper based on molecular imprinted biomimetic antibody exhibited a linear relation in the range of 1×10-3-1 mg L-1, with a correlation R2=0.990, inhibition rate can reach 69.8%, the half inhibitory concentration (IC50) was 0.116 mg L-1 and the detection limit (IC15) was 2.1×10-3 mg L-1. The precision for three replicate detections of carbaryl (1mg L-1) was 1.69% (relative standard deviation). Through a series of analysis, we think the method of biomimetic enzyme-linked immunosorbent assay by paper based on molecular imprinted biomimetic antibody can be used for rapid detection of carbaryl.(3) Functional ionic liquid 1-vinyl-3-hexylimidazolium hexafluoride phosphate as auxiliary medium, modified quantum dots by electrostatic interactions, making it effectively participate in the preparation of molecular imprinted polymer. Carbaryl as template, methacrylic acid as functional monomer, ethylene glycol dimethyl acrylate as the crosslinking agent,2,2’-azodiisobutyronitrile as initiator, synthetic an ionic liquid modified quantum dots fluorescent molecular imprinting sensing materials through traditional thermal polymerization, achieving the purpose of quantitative detection of carbaryl with the change of intensity of fluorescence which caused by adsorption carbaryl. Under optimum conditions, the methods of ionic liquid modified quantum dots fluorescent molecular imprinting sensing materials exhibited a linear relation in the range of 4.97×10-7-3.98×10-4 moL L-1, with a correlation R2=0.9954, The limit of detection was 1.47×10-7 moL L-1. The precision for five replicate detections of carbaryl (10 mg L-1) was 2.4% (relative standard deviation). The reproducibility was also investigated. Three times replicate measurements were carried out and the relative standard deviation was 3.8%. Through a series of analysis, we think the method of ionic liquid modified quantum dots fluorescent Molecular imprinting sensing materials can be used for rapid detection of carbaryl.