[Confirmatory reactions for the identification of patulin in apple juice by thin layer chromatography]

To avoid misinterpretations in identifying mycotoxins by means of thin-layer chromatography (silica gel), it is necessary to make use of a second method of identification. The reaction with phenylhydrazine and with 2,4-dinitrophenylhydrazine on the plate is suited for patulin. The thus obtained hydrazones are transferred to a second thin-layer chromatographic plate and separated using toluene/acetic acid ethyl ester/85% formic acid (50 + 40 + 10, v/v) or chloroform/acetone (68 + 32, v/v). This method of identification may be used, for example, for apple juices with a patulin content equal or greater than 500 microgram/l.