DETECTION OF 2,4-DICHLOROPHENOXYACETIC ACID USING A FLUORESCENCE IMMUNOANALYZER

A flow immunoassay method for the measurement of 2,4-dichlorophenoxyac etic acid (2,4-D) was developed. The competitive fluorescence immunoas say relies on the use of antibody- or antigen-coated poly(methyl metha crylate) particles (98 mu m diameter) as a renewable solid phase. The assay exhibits a dynamic range of 0.1-100 mu g l(-1) using a monoclona l antibody or alternatively 10 mu g l(-1) to 10 mg l(-1) using commerc ially available antiserum. The assay is demonstrated in buffered salin e solution as well as in aquatic environmental media, The relative err ors for the environmental matrices were similar to those for the buffe r control, The precision of concentration values calculated at 1 mg l( -1) (for the assay using antiserum) mere +/-0.28, +/-0.27 and +/-0.43 mg l(-1) for the buffer, well mater and river water matrices, respecti vely. The method shows cross-reactivity with compounds of closely rela ted structure but little cross-reactivity with compounds dissimilar in structure to 2,4-D. The proposed automated competitive immunoassay me thod is rapid (between 7 and 15 min per assay), simple and potentially portable.