UHPLC-MS/MS highly sensitive determination of aflatoxins, the aflatoxin metabolite M1 and ochratoxin A in baby food and milk

In this work, a method has been developed for the ultrasensitive and selective determination of various regulated mycotoxins (aflatoxins G1, G2, B1, B2, M1, and ochratoxin A) in baby food commodities and milk, using ultra high pressure liquid chromatography (UHPLC) coupled to tandem mass spectrometry (MS/MS). The high sensitivity required for these compounds made necessary the application of a pre-concentration step based on solid phase extraction with immunoaffinity columns, after sample extraction with acetonitrile:water (80:20). Thanks to the fast high-resolution of UHPLC and the enhanced selectivity obtained with the triple quadrupole mass analyser in SRM mode, the chromatographic separation was achieved in only 4 min. Validation of the method was carried out in four different matrices (cereals infant formula, powdered milk for babies, milk with cereals for infants, and raw milk) by recovery experiments, using samples spiked at 0.025 and 0.1 mu g kg(-1) in quintuplicate. Satisfactory recoveries, between 80% and 110%, with RSDs lower than 15%, were obtained in all food matrices tested. Quantification was performed by external calibration with standards in solvent. The developed method has been applied to the analysis of samples collected from local markets. Positive findings were confirmed by acquiring two transitions (Q quantification, q confirmation) and evaluating their Q/q ratio. (C) 2010 Elsevier Ltd. All rights reserved.