SENSITIVE ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR THE MYCOTOXIN ZEARALENONE IN BARLEY AND JOBS-TEARS

An easy, sensitive, competitive indirect enzyme-linked immunosorbent a ssay (CI-ELISA) for zearalenone in barley and Job's-tears was establis hed. To improve sensitivity of the assay system for zearalenone, a sol id phase antigen was prepared by affinity purification. This assay sys tem uses a purified antigen and specific monoclonal antibodies for zea ralenone. Consequently, the detection limit of zearalenone by CI-ELISA was increased to 0.2 ng/mL (equivalent to 10 ng/g in barley and Job's -tears). Zearalenone in barley and Job's-tears samples could be determ ined in the range of 25-1000 ng/g using method A (methanol-water and d ichloromethane extraction) and method B (methanol-water alone) as samp le preparation. The average recoveries of zearalenone from barley samp les were observed to be 106% (mean CV, 10.3%) by method A and 98% (mea n CV, 7.5%) by method B; also, those of zearalenone from Job's-tears s amples were observed to be 96% (mean CV, 9.4%) by method A and 102% (m ean CV, 6.5%) by method B. There was little or no difference between m ethod A and method B for the recovery. For the benefit of a facile sam ple preparation, unknown amounts of zearalenone in barley and Job's-te ars samples were assayed by method B. The results obtained by CI-ELISA were closely correlated with those of high-performance Liquid chromat ography.