Determination of citrinin in corn and barley on thin layer chromatographic plates impregnated with glycolic acid

A method is described for the determination of citrinin in corn and barley. The mycotoxin is extracted with a mixture of acetonitrile-10% glycolic acid in water, defatted with isooctane, and transferred to chloroform according to published methods. The mycotoxin is separated by thin layer chromatography (TLC) on plates previously impregnated with 10% glycolic acid solution in ethanol; identity is confirmed by chemical tests. Citrinin is then quantitated by the limit detection method. Recoveries of citrinin from corn and barley samples spiked at levels of 50, 80, 150, 300, 500, and 1000 micrograms/kg were in the range 91-98%. The minimum detectable concentration is 15-20 micrograms/kg. Recoveries obtained with and without glycolic acid in the extraction solvent were compared. Sensitivities on TLC plates (limits of detection, micrograms/spot) impregnated with glycolic acid were compared with those on plates impregnated with oxalic acid.