Abstract: A method was developed for the simultaneous determination of patulin in juice by solid phase extraction (SPE)-ultra performance liquid chromatography coupled with electro-spray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). The cloudy juice was hydrolyzed by enzyme and extracted by ethyl acetate. The extract of cloudy juice was then enriched and purified by an HLB SPE cartridge. If the juice was clear it was directly treated by the cartridge as above．The separation was performed on a C18 column with the gradient elution of acetonitrile and water. The patulin was detected by MS with electrospray negative ionization (ESI~) in the mode of multiple reaction monitoring (MRM). The good linearity was observed in the range of 1.0~500 μg/L with the correlation coefficient of 0.999 and the limit of quantitation of 5.0 μg/kg. The recoveries were in the range of 80.6%~91.8% at three spiked levels of 5.0, 25.0 and 100.0 μg/kg with the relative standard deviations of 1.5%~7.3%. It was proved to be a simple, reliable and accurate method which can fully meet the requirements of patulin detection in juice samples according to most domestic and international legislations.

Key words: juice, patulin, solid phase extraction (SPE), ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)