Determination of citrinin in corn and barley.

A method is described for determining citrinin in corn and barley. The initial extraction uses an aqueous acidified acetonitrile solution, and the resulting solution is partially purified by several partition steps. Citrinin is determined by using either high pressure liquid chromatography (HPLC) or thin layer chromatography (TLC). For HPLC, the extract is injected on a reverse phase column, eluted with either 0.25N H3PO4-methanol (45 + 55) or 0.25N H3PO4-acetonitrile (50 + 50), and detected by fluorescence (excitation 325--385 nm, emission above 451 nm). Recovery of added citrinin from corn by this method is 60--87% at levels of 50--4000 microgram/kg. For TLC, the chromatographic plates are impregnated with oxalic acid by dipping them in an oxalic acid-methanol solution before spotting and development. Recovery of added citrinin from corn, using TLC, is 40--100% at levels of 50--40000 microgram-kg.