Hplc detection of patulin in apple juice with GC/MS confirmation of patulin identity

The official patulin LC procedure was further examined (AOAC 995.10). Juice or juice concentrate was extracted with ethyl acetate and cleaned up with sodium carbonate. Patulin in the dried extract was determined by reversed-phase LC with UV detection (280 nm) in 1% THF aqueous solution after evaporation of the ethyl acetate. An end-capped C18 column was required to separate patulin from hydroxymethylfurfural. Patulin was detected in approximately half of the >1000 extracts examined. Only ca 10% of the extracts contained patulin at levels greater than 50 microg/L (50 ppb). Some presumptive findings were confirmed by capillary gas chromatography/mass spectrometry as the trimethyl silyl derivative using electron ionization or as underivatized patulin using negative ion chemical ionization. Trifluoropropylmethyl polysiloxane capillary columns provided superior gas chromatography of underivatized patulin compared to phenyl/methyl polysiloxane and methyl polysiloxane columns.