A sensitivity-improved enzyme-linked immunosorbent assay for fenvalerate: a new approach for hapten synthesis and
1Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457, China.
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).
Conclusion:
In this study, a simple and efficient immunoassay method was developed. It is preferable for the rapid determination of fenvalerate residues in tea samples.
