title: Highly sensitive and specific detection of neonicotinoid insecticide imidacloprid in environmental and food samples by a polyclonal antibody-based enzyme-linked immunosorbent assay.
abstract: BACKGROUND
  Imidacloprid is one of the main neonicotinoid insecticides widely used in agriculture owing its broad spectrum of activity and low bioaccumulation. However, imidacloprid is toxic to honey bees and other beneficial organisms, and its residues may occur in environmental and food samples, posing a potential hazard to consumers. In this study the imidacloprid derivative bearing a three-atom length spacer was synthesized and coupled to carrier proteins. Highly sensitive and specific polyclonal antibodies against imidacloprid were successfully produced and the polyclonal antibody-based enzyme-linked immunosorbent assay (pAb-ELISA) was developed.
  
  
  RESULTS
  The ELISA standard curve was constructed within the concentration range 0.1-100 ng mL(-1). The IC(50) value for nine standard curves was in the range 1.2-3.0 ng mL(-1) and the limit of detection was 0.03-0.16 ng mL(-1). The sensitivity of the assay was one order of magnitude higher than that in most published papers. There was almost no cross-reactivity of the antibody with four structurally related compounds (acetamiprid, nicotine, clothianidin and nitenpyram) and six other compounds, indicating that the assay displays not only high sensitivity but also high specificity. No detectable imidacloprid was found in 11 collected environmental and food samples by the assay. For imidacloprid-spiked samples, acceptable recoveries of 73.4-94.4% and intra-assay coefficients of variation of 2.2-12.8% were obtained. The assay was also validated with high-performance liquid chromatography (HPLC) and a good correlation of ELISA with HPLC was achieved.
  
  
  CONCLUSIONS
  The proposed ELISA provides a sensitive, specific, simple and cost-effective quantitative/screening method for detecting imidacloprid in environmental and food samples.
authors.affiliation: College of Chemistry, Sichuan University, Chengdu 610064, China.
authors.forename: Rongmei
authors.initials: R
authors.lastname: Wang
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
authors.forename: Yuzheng
authors.initials: Y
authors.lastname: Wang
authors.forename: Anping
authors.initials: A
authors.lastname: Deng
mesh_terms: D000818:Animals; D000906:Antibodies; D001516:Bees; D002851:Chromatography, High Pressure Liquid; D003247:Conservation of Natural Resources; D003429:Cross Reactions; D004784:Environmental Monitoring / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D007093:Imidazoles / Q000032:analysis* / Q000276:immunology; D020128:Inhibitory Concentration 50; D007306:Insecticides / Q000032:analysis* / Q000276:immunology; D057230:Limit of Detection; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000032:analysis* / Q000276:immunology
chemical_list: D000906:Antibodies; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid