Abstract: A method for the determination of folic acid in food by ultra performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS) has been established. Sample extract was separated on Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) using a mobile phase consisting of acetonitrile and 0.1% formic acid (5:95, V/V) at a flow rate of 0.25 mL/min, and analyzed by electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in a positive-ion selective reaction monitoring (SRM) mode at a collision energy of 14 eV using m/z 442.3, m/z 295.1 and m/z 176.0 as the parent, quantitative and qualitative ions, respectively. The column temperature and the injection volume were set as 40 ℃ and 2 μL, respectively. The average blank spike recoveries for 4 replicate determinations across three spike levels were in the range of 80.7%－89.7% with RSD of 2.90%－3.85%. The limit of detection was 1 ng/mL. An excellent linear relationship was achieved in the range of 0.001－1.000 μg/mL. The method was characterized by simple operation, time saving and high sensitivity.

Key words: folic acid, food, determination, ultra performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS)