Development of method for determination and quantification of Alternaria mycotoxins in food by high resolution mass spectrometry

High-resolution liquid chromatography-mass spectrometry (LC-HRMS) is a highly sensitive, specific and accurate method for the simultaneous detection and quantification of three mycotoxins Alternaria (Alternariol (AOH), Alternariol Monomethyl Ete) (AME), Tenuazonic acid (TeA)). Chromatographic conditions include: column reversed phase C18, mobile phases in gradient mode with two channels of H2O and MeOH containing 0.1 % formic acid and 10 mM ammonium formate. HRMS high resolution mass spectrometer detector with negative electron ionization (ESI-) source is used. Samples were cleaned and enriched using an Oasis HLB solid phase extraction column. The method has a limit of quantitation (LOQ) for AOH and AME of 1.0 µg/kg and TeA of 1.0 µg/kg with recovery from 80.0 to 114.8 %, repeatability from 0.07 - 9.9 %, meeting the requirements of AOAC and European regulations. The method was applied to detect and quantify Alternaria mycotoxins in 80 food samples collected in Hanoi city. AOH was detected in 04/20 vegetable samples (3.3 - 178 µg/kg), 03/20 fruit samples (5.6 - 7.3 µg/kg), 06/20 cereal samples (13.4 - 17.4 µg/kg), 03/20 oil seed samples (13.2 - 25.2 µg/kg); detected AME in 01/20 vegetable samples (7.5 µg/kg), 02/20 fruit samples (< 3 µg/kg), 01/20 cereal samples (9.5 µg/kg), 02/20 oil seed samples (< 3 µg/kg); detected TeA in 02/20 vegetable samples (9.0 µg/kg), 01/20 cereal samples (< 3 µg/kg), 02/20 oil seed samples (< 3 µg/kg), not detected in fruit samples.