Rapid detection of aflatoxin B1, zearalenone and ochratoxin A in grains by thermal desorption dielectric barrier discharge ionization mass spectrometry

Dielectric barrier discharge ionization is increasingly used for rapid detection in ambient mass spectrometry, although more often for gaseous and highly volatile samples than for solids and liquids. In this project, we present a rapid and sensitive method for detecting mycotoxins and demonstrate its capability for the detection of aflatoxin B1, zearalenone, and ochratoxin A in food samples. Our method is based on thermal desorption coupled to dielectric barrier discharge ionization mass spectrometry (TD-DBDI-MS), which we show generates minimal interferences and produces almost exclusively molecular ions. We detected mycotoxins in various food samples, including corn, peanuts, millet, and rice. Our method has a linear dynamic range of 1 mu g kg-1 to 100 mu g kg-1 for all three mycotoxins and a limit of detection (LOD) of 0.31 mu g kg-1, 0.28 mu g kg-1 and 0.43 mu g kg-1, respectively. It is simple, rapid, reduces the pretreatment steps and has significant potential for practical applications. Extraction followed by thermal desorption and dielectric barrier discharge ionization-MS is able to quantify mycotoxins in grains down to the ppm level.