Trace analysis of multiple synthetic phenolic antioxidants in foods by liquid chromatography–tandem mass spectrometry with complementary use of electrospray ionization and atmospheric pressure chemical ionization

This study presented a universal LC–MS/MS method for trace analysis of multiple synthetic phenolic antioxidants (SPAs) in foods by complementary use of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). The analytes included not only the well-known BHT and BHA but also 18 high molecular weight SPAs. The method utilized APCI to achieve sensitive analysis of BHT, Irganox 1010, Irganox 330, and Irganox 3125 based on the finding that APCI significantly improved the sensitivity of these weakly acidic or slightly polar SPAs, and utilized ESI to obtain sensitive analysis of other SPAs. Additionally, the method avoided background contamination by using effective measures including installation of a trapping column in the LC system. Method performance assessment showed satisfactory sensitivity, linearity, accuracy, and precision for analysis of SPAs in vegetable oil, milk powder, and baby fruit puree. Method application revealed widespread contamination of foods with BHT, Irganox 1010, and Irganox 1076.