Quantification of 2,4-dichlorophenoxyacetic acid in oranges and mandarins by chemiluminescent ELISA

• Published in: Food chemistry 2013-11, Vol.141 (2), p.865-868
• Main Authors: Vdovenko, Marina M., Stepanova, Alexandra S., Eremin, Sergei A., Van Cuong, Nguyen, Uskova, Natalia A., Yu Sakharov, Ivan
• Format: Article
• Language: English
• Subjects: 2,4-Dichlorophenoxyacetic acid; 2,4-Dichlorophenoxyacetic Acid - analysis; Chemiluminescence; Citrus sinensis - chemistry; Drug Residues - analysis; ELISA; Enzyme-Linked Immunosorbent Assay - methods; Fruit - chemistry; Herbicides - analysis; Limit of Detection; Luminescent Measurements - methods; Mandarin; Orange; Peroxidase; Soya
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2013.04.060

•Direct competitive CL-ELISA for 2,4-dichlorophenoxyacetic acid was developed.•The values of the lower detection limit, IC50 and the working range were determined.•Extracts of orange and mandarin peel did not show a matrix effect.•The content of 2,4-D in oranges and mandarins was estimated by CL-ELISA. Direct competitive enzyme-linked immunosorbent assay (ELISA) for 2,4-dichlorophenoxyacetic acid (2,4-D) was developed. Varying the concentrations of monoclonal anti-2,4-D-antibody and the conjugate of soybean peroxidase and 2,4-D the conditions of ELISA performance were optimised. The chemiluminescent method based on peroxidase-catalysed oxidation of luminol was applied to measure the enzyme activity of the conjugate. A mixture of 3-(10′-phenothiazinyl)propane-1-sulfonate and 4-morpholinopyridine was used as potent enhancer of chemiluminescence signal. It was shown that the values of the lower detection limit, IC50 and the working range were 1.5, 64.0, and 6.5–545ng/mL, respectively. The recovery values of CL-ELISA from 10 spiked samples of oranges (n=5) and mandarins (n=5) cultivated in green house without use of 2,4-D and containing different 2,4-D concentrations (10–300ng/mL) were ranged from 92% to 104% that indicated on the absence of matrix effect for the fruit extracts of interest. Determination of 2,4-D in peel of five oranges and five mandarins purchased from stores in Vietnam showed that 2,4-D content in oranges fruits (79–104μg/kg) was significantly higher than that in mandarins (1.66–2.82μg/kg).