[Enzyme immunoassay (EIA) for the estrogenic stilbene derivative diethylstilbestrol (DES) (author's transl)]

An enzyme immunoassay (EIA) for diethylstilbestrol (DES) is described, which is based on the competitive reaction between DES and peroxidase-labelled DES for an antibody, which has been bond to an insoluble support. The preparation of the enzyme-labelled DES necessitates the use of highly purified 4-O-(carboxypropyl)-diethylstilbestrol (CP-DES) to obtain a highly immunoreactive conjugate. CP-DES was synthesized from DES and ethyl-4-bromobutylate and was purified by a novel isolation procedure involving a simple solvent partition followed by hydrolysis of the ester. It was characterized by it's chemical and biological properties. The assay covers the range from 0.2 to 20 pmol/test (approximately equal to 0.05-5 ng/test). It has sufficient sensitivity and specificity compared with radio immuno assay to make it a potential method for controlling the misuse of this estrogenic substance in animal production.