Syringe-cartridge solid-phase extraction method for patulin in apple juice.

A syringe-cartridge solid-phase extraction (SPE) method was developed for determination of patulin in apple juice. A 2.5 mL portion of test sample was passed through a conditioned macroporous SPE cartridge and washed with 2 mL 1% sodium bicarbonate followed by 2 mL 1% acetic acid. Patulin was eluted with 1 mL 10% ethyl acetate in ethyl ether and determined by reversed-phase liquid chromatography using a mobile phase consisting of 81% acetonitrile, 9% water, and 10% 0.05M potassium phosphate buffer, pH 2.4. Recoveries averaged 92% and the relative standard deviation was 8.0% in test samples spiked with 50 ng/mL patulin. The method appears to be applicable for monitoring apple juice samples to meet the U.S. Food and Drug Administration compliance action level of 50 microg/kg in an industrial quality assurance laboratory environment.

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.