Detection of 2,4-Dichlorophenoxyacetic Acid Using a Fluorescence Immunoanalyzer

Abstract

A flow immunoassay method for the measurement of 2,4-dichlorophenoxyacetic acid (2,4-D) was developed. The competitive fluorescence immunoassay relies on the use of antibody- or antigen-coated poly(methyl methacrylate) particles (98 microns diameter) as a renewable solid phase. The assay exhibits a dynamic range of 0.1-100 micrograms l-1 using a monoclonal antibody or alternatively 10 micrograms l-1 to 10 mg l-1 using commercially available antiserum. The assay is demonstrated in buffered saline solution as well as in aquatic environmental media. The relative errors for the environmental matrices were similar to those for the buffer control. The precision of concentration values calculated at 1 mg l-1 (for the assay using antiserum) were +/- 0.28, +/- 0.27 and +/- 0.43 mg l-1 for the buffer, well water and river water matrices, respectively. The method shows cross-reactivity with compounds of closely related structure but little cross-reactivity with compounds dissimilar in structure to 2,4-D. The proposed automated competitive immunoassay method is rapid (between 7 and 15 min per assay), simple and potentially portable.

Organophosphorus Hydrolase-Based Assay for Organophosphate Pesticides

“…The KinExA fluorescence analyzer was purchased from Sapidyne Inc. (Boise, ID). Its features and basic operation have been previously described (14). For the OPH‐based assay, FITC‐labeled enzyme‐coated beads were trapped on a nylon screen in a capillary which provided the optical flow cell in the filter‐type fluorimeter.…”

Inhibition-Based Biosensors for the Detection of Environmental Contaminants: Determination of 2,4-Dichlorophenoxyacetic Acid

“…For these reasons a reliable and rapid technique for the determination of 2,4-D in aqueous samples is increasingly necessary. Apart from classic HPLC and GC-MS techniques, several immunosensors recently have been developed for the determination of 2,4-D [30][31][32][33][34][35]. The goal of this work was the development of a biosensor capable not only of detecting a single chemical species, but also of giving a global evaluation of the overall contamination of the sample by 2,4-D and its analogs, which are endowed with the same toxicity.…”

Inhibition‐based biosensors for the detection of environmental contaminants: Determination of 2, 4‐dichlorophenoxyacetic acid

“…For these reasons a reliable and rapid technique for the determination of 2, 4‐D in aqueous samples is increasingly necessary. Apart from classic HPLC and GC‐MS techniques, several immunosensors recently have been developed for the determination of 2, 4‐D [30–35]. The goal of this work was the development of a biosensor capable not only of detecting a single chemical species, but also of giving a global evaluation of the overall contamination of the sample by 2, 4‐D and its analogs, which are endowed with the same toxicity.…”