Abstract:

Objective   To develop a solid-phase extraction method coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for determination of three fumonisins (fumonisin B1, fumonisin B2 and fumonisin B3) in wheat flour, corn and corn-based products．  Methods   The samples were extracted by 50%(V/V) acetonitrile-water, followed by cleaning up on a MultiSep 211 column. Three toxins were eluted by methanol-formic acid(99∶1, V/V) and analyzed by UPLC-MS/MS with gradient elution. Acetonitrile and 0.2%(V/V) formic acid-water were used as the mobile phases in the gradient elution． The mass spectrometric acquisitions were carried out by means of multiple reaction monitoring (MRM) in electrospray positive ionization mode． Results   The limits of detection (LOD) and the limits of quantification (LOQ) for three fumonisins were 0.2μg/kg and 0.6μg/kg. The mean recoveries of three fumonisins at the different spiked levels ranged from 69.44% to 114.69%. 39 corn samples and 30 wheat flour samples collected from Gansu and Tianjin harvested in 2011 were analyzed with the developed method. Fumonisin B1 was the predominant toxin detected in terms of frequency and contamination level. Conclusion   The developed method is simple， sensitive and reproducible，and meets the requirement for determination of the three fumonisins in wheat flour, corn and corn-based products．

Key words: Fumonisin; Wheat flour; Corn; Ultra performance liquid chromatographytandem mass spectrometry(UPLC-MS/MS)