POLYCLONAL AND MONOCLONAL ENZYME IMMUNOASSAYS FOR PICLORAM DETECTION IN WATER, SOIL, PLANTS, AND URINE

Two indirect enzyme immunoassays for picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) detection were compared in terms of sensitivity, accuracy, and precision. The assay using a rabbit antipicloram serum had a linear working range from 5 to 5000 ng/mL with a mean l50 value of 140 ng/mL and a lower detection limit of 5 ng/mL. The assay using a monoclonal antibody obtained from a mouse hybridoma cell line yielded a linear working range from 1 to 200 ng/mL with a mean 150 value of 10 ng/mL and a lower detection limit of 1 ng/mL. Neither assay showed appreciable cross-reactivity with the structurally related pyridine herbicides clopyralid, fluroxypyr, and triclopyr or with the phenoxyacetic acid herbicide 2,4-D. From the analysis of fortified river water, soil extracts, plant extracts, and urine, the monoclonal antibody based assay was shown to be more sensitive, more accurate, and more precise than the polyclonal antiserum based assay. Only the monoclonal assay was suitable for quantitative determinations of picloram. © 1990, American Chemical Society. All rights reserved.