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Dopant-Assisted Atmospheric Pressure Photoionization of Patulin in Apple Juice and Apple-Based Food with Liquid Chromatography–Tandem Mass Spectrometry

Zhang, Kai, Wong, Jon W., Mai, Huy, Trucksess, Mary W.
Journal of agricultural and food chemistry 2014 v.62 no.18 pp. 4112-4118
apple cider, apple juice, applesauce, atmospheric pressure, formic acid, fortified foods, infant foods, liquid chromatography, markets, patulin, solvents, tandem mass spectrometry, toluene
A dopant-assisted atmospheric pressure photoionization (APPI) with liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to determine patulin in apple juice and apple-based food. Different dopants, dopant flow rates, and LC separation conditions were evaluated. Using toluene as the dopant, the LC-APPI-MS/MS method achieved a linear calibration from 12.5 to 2000 μg/L (r2 > 0.99). Matrix-dependent limits of quantitation (LOQs) were from 8 μg/L (solvent) to 12 μg/L (apple juice). [13C]-Patulin-fortified apple juice samples were directly analyzed by the LC-APPI-MS/MS method. Other apple-based food was fortified with [13C]-patulin, diluted using water (1% formic acid), centrifuged, and filtered, followed by LC-APPI-MS/MS analysis. In clear apple juice, unfiltered apple cider, applesauce, and apple-based baby food, average recoveries were 101 ± 6% (50 μg/kg), 103 ± 5% (250 μg/kg), and 102 ± 5% (1000 μg/kg) (av ± SD, n = 16). Using the suggested method, patulin was detected in 3 of 30 collected market samples with concentrations ranging from <LOQ to 18 μg/L. The use of [13C]-patulin allowed quantitation using solvent calibration standards with satisfactory precision and accuracy.