Modified QuEChERS method combined with ultra-high performance liquid chromatography tandem mass spectrometry for the simultaneous determination of 26 mycotoxins in sesame butter

A high-throughput method for the simultaneous determination of 26 mycotoxins in sesame butter was developed by coupling the modified Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method with ultra-high performance liquid chromatography triple quadrupole mass spectrometry (UHPLC-MS/MS). The samples were sequentially extracted using 20 mL (80:20, v/v) and 5 mL (20:80, v/v) acetonitrile aqueous solutions, followed by salting out by the addition of magnesium sulfate and sodium chloride. Finally, the samples were purified using hexane and dispersed C18 solid phase extraction (dSPE). The mycotoxins were further separated using a C18 column and detected by electrospray ionization (ESI) in the multiple reactions monitoring (MRM) mode. Using this detection technique, 16 mycotoxins were detected as positive ions using methanol and water containing 0.1% formic acid as the mobile phase, whereas the other 10 mycotoxins were detected as negative ions using methanol and water as the mobile phase. With the matrix-matched quantification calibration, the developed method showed a good linear dynamic range with regression coefficients of 0.995 or higher. This method allowed for the detection of the 26 mycotoxins at LOQs significantly lower than the available maximum residue levels currently regulated by EU regulations. Additionally, at the three spiking levels examined, the majority of recoveries were within 60-120%, with RSDs within 15%. The method developed herein has the advantages of high sensitivity, accuracy and throughput, and it can be applied to the target screening of mycotoxins in real samples. (C) 2014 Elsevier B.V. All rights reserved.