SENSITIVE DETERMINATION OF ZEARALENONE AND ALPHA-ZEARALENOL IN BARLEYAND JOB-TEARS BY LIQUID-CHROMATOGRAPHY WITH FLUORESCENCE DETECTION

A sensitive and reliable method for liquid chromatographic (LC) determ ination of zearalenone and alpha-zearalenol in barley and Job's-tears was investigated. The method by which these toxins were determined inv olves addition of an internal standard (zearalenone 6'-oxime) to barle y and Job's-tears samples. Extracts from grain samples were cleaned up by passage through chromatography on piperidinohydroxypropyl Sephadex LH-20 as a lipophilic gel. Individual toxins were resolved by LC on a reversed-phase (ODS) column with fluorescence detection. The detectio n limit is estimated to be 0.2 ng for zearalenone and alpha-zearalenol standards. Known amounts of zearalenone and alpha-zearalenol (25-1250 ng) were added to a barley sample (5 g). Average recoveries for alpha -zearalenol and zearalenone, respectively, ranged from 96 to 102% (mea n CV, 3.6%) and from 96 to 103% (mean CV, 3.3%). This method is applic able to determination of alpha-zearalenol and zearalenone in barley an d Job's-tears with satisfactory sensitivity and accuracy.