title: Determination of isopropyl thioxanthone (ITX) in fruit juices by pressurized liquid extraction and liquid chromatography-mass spectrometry.
abstract: A rapid LC-MS method, which compares different mass analyzers-single quadrupole, ion trap, and triple quadrupole-was developed for the quantitative determination of isopropyl thioxanthone (ITX) in fruit juices. ITX, a photoinitiator in UV-cured inks that can reach foods from the cartons for beverages in which they are used, was extracted from fruit juice samples with acetone/hexane (50:50) using pressurized liquid extraction. This method gave detection limits of 3, 3, and 0.01 microg/L and quantification limits of 10, 10, and 0.05 microg/L using single quadrupole, ion trap, and triple quadrupole, respectively. Five replicate fortifications of different fruit juices at the quantification limit gave recoveries oscillating between 68 and 72% with CV varying between 14 and 18%. This is the first report of a positive mass spectrometric identification and quantification of ITX in fruit juice samples packed in TetraPack. The sensitivity and specificity of the LC-MS/MS analysis using the triple quadrupole enables it to be the method of choice for risk assessment and monitoring. The method was applied to apricot, orange, peach, apple, grape and pineapple, and cherry and strawberry juices and to fruit nectars from Spain and Italy, and the ITX was detected in the range of 0.05-0.78 microg/L.
authors.affiliation: Dipartimento di Scienze Chimiche, Facoltà di Farmacia, Università degli Studi di Camerino, via S. Agostino 1, 62032 Camerino (MC), Italy.
authors.forename: Gianni
authors.initials: G
authors.lastname: Sagratini
authors.forename: Jordi
authors.initials: J
authors.lastname: Mañes
authors.forename: Dario
authors.initials: D
authors.lastname: Giardina
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Picó
mesh_terms: D001628:Beverages / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D005506:Food Contamination / Q000032:analysis*; D005638:Fruit / Q000737:chemistry*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization; D044004:Xanthones / Q000032:analysis*
chemical_list: D044004:Xanthones; C514852:isopropyl thioxanthone