title: A sensitivity-improved enzyme-linked immunosorbent assay for fenvalerate: a new approach for hapten synthesis and application to tea samples.
abstract: BACKGROUND
  Fenvalerate has been widely used for the control of many common pests, but residues of this pesticide have been found in some agricultural crops. China is a large exporter of tea products; thus monitoring of pesticide residues in tea products has become increasingly important. In this study, a method of competitive direct enzyme-linked immunosorbent assay (CD-ELISA) for the rapid detection of fenvalerate in tea sample was developed.
  
  
  RESULTS
  A polyclonal antibody against fenvalerate (FEN) was produced by the hapten with the characteristic moiety of fenvalerate. After acidification, the hapten was synthesized from 2-(4-chloro-phenyl)-3-methyl-butyric acid and aminocaproic acid methyl ester. The CD-ELISA method developed has a high sensitivity of detection: 9 µg L(-1) for IC(50) and 0.5 µg L(-1) for IC(15) . Fenvalerate was treated with 0.5 mmol L(-1) NaOH-methanol solution to improve its solubility by isomerization. In the tea sample, the detection limit of fenvalerate was 0.16 mg L(-1) . A recovery rate of 76.67-91.43% was obtained from spiked tea. The reliability of the CD-ELISA method is better in comparison with the gas chromatographic method (R(2) = 0.9968).
  
  
  CONCLUSIONS
  In this study, a simple and efficient immunoassay method was developed. It is preferable for the rapid determination of fenvalerate residues in tea samples.
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.forename: Yang
authors.initials: Y
authors.lastname: Lu
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.forename: Na
authors.initials: N
authors.lastname: Xu
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002681:China; D003429:Cross Reactions; D004785:Environmental Pollutants / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005506:Food Contamination; D006241:Haptens / Q000737:chemistry*; D007306:Insecticides / Q000032:analysis*; D007536:Isomerism; D057230:Limit of Detection; D009570:Nitriles / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D011722:Pyrethrins / Q000032:analysis*; D011817:Rabbits; D015203:Reproducibility of Results; D012995:Solubility; D013662:Tea / Q000737:chemistry*
chemical_list: D004785:Environmental Pollutants; D006241:Haptens; D007306:Insecticides; D009570:Nitriles; D010573:Pesticide Residues; D011722:Pyrethrins; D013662:Tea; C017690:fenvalerate