Development of an Enzyme-Linked Immunosorbent Assay for the Detection of Dicamba

• Published in: Journal of agricultural and food chemistry Vol. 49; no. 5; pp. 2168 - 2174
• Main Authors: Clegg, B. Stephen, Stephenson, Gerald R, Hall, J. Christopher
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.05.2001
• Subjects: Agronomy. Soil science and plant productions; Analysis methods; Applied sciences; Biological and medical sciences; Cross Reactions; Dicamba - analysis; Enzyme-Linked Immunosorbent Assay - methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Herbicides - analysis; Natural water pollution; Pesticide Residues - analysis; Pollution; Sensitivity and Specificity; Soil and sediments pollution; Soil and water pollution; Soil science; Water - chemistry; Water treatment and pollution; Auxin; Pesticides; Detection threshold; Water pollution; Measurement method; Soil pollution; ELISA assay; Herbicide; Comparative study; Tailings
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf001136j

A competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) was developed to quantitate the herbicide dicamba (3,6-dichloro-2-methoxybenzoic acid) in water. The CI-ELISA has a detection limit of 2.3 μg L-1 and a linear working range of 10−10000 μg L-1 with an IC50 value of 195 μg L-1. The dicamba polyclonal antisera did not cross-react with a number of other herbicides tested but did cross-react with a dicamba metabolite, 5-hydroxydicamba, and structurally related chlorobenzoic acids. The assay was used to estimate quantitatively dicamba concentrations in water samples. Water samples were analyzed directly, and no sample preparation was required. To improve detection limits, a C18 (reversed phase) column concentration step was devised prior to analysis, and the detection limits were increased by at least by 10-fold. After the sample preconcentration, the detection limit, IC50, and linear working range were 0.23, 19.5, and 5−200 μg L-1, respectively. The CI-ELISA estimations in water correlated well with those from gas chromatography−mass spectrometry (GC-MS) analysis (r 2 = 0.9991). This assay contributes to reducing laboratory costs associated with the conventional GC-MS residue analysis techniques for the quantitation of dicamba in water. Keywords: Dicamba; ELISA; 3,6 dichloro-2-methoxybenzoic acid; herbicide; residue; immunoassay; gas chromatography mass spectrometry; GC-MS; analysis