Radioimmunoassay of T-2 toxin in corn and wheat

A radioimmunoassay (RIA) for the determination of T-2 toxin in corn and wheat was developed. The toxin was first extracted with methanol, and the methanolic extract was washed with hexane and passed through a Sep-Pak C18 reverse phase cartridge. The extract was then evaporated to remove the organic solvent, diluted with 0.1M sodium phosphate buffer (pH 7.2), and subjected to RIA using an ammonium sulfate precipitation method to separate the free T-2 toxin from the antigen-antibody complex. The recovery of T-2 toxin after the extraction and cleanup steps was 78-85% for corn and 90-95% for wheat. Sep-Pak cleanup removed a considerable amount of interfering substances from the sample, thus enabling the detection of 1 and 2.5 ppb of T-2 toxin in the wheat and corn samples, respectively. The recovery by RIA methods of T-2 toxin added to the corn and wheat samples was between 84 and 103% in the ranges of 1-20 ppb (for wheat) and 2.5-20 ppb (for corn). The new RIA proved to be a sensitive, accurate, reproducible, and relatively simple method for determining T-2 toxin.