Establishment of QuEChERS-UPLC-MS/MS method to determine three kinds of ochratoxins in coffee

Objective： A new method was developed for the simultaneous determination of three kinds of ochratoxins in coffee by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with QuEChERS pretreatment. Methods： Samples were extracted by acetonitri-water-formic acid solution (55∶40∶5) with ultrasonic, salted out with a QuEChERS salt pocket, and then purified with a (ZanChERS-Myco17) column. The chromatographic separation was performed on an ACQUITY UPLC BEH C18 (1.7 μm, 2.1 mm×100 mm) column by gradient elution using a mobile phase comprising 0.2% formic acid aqueous solution and acetonitrile. In the positive ion mode of electric spray, the samples detected were used by multiple reaction monitoring (MRM) modes with internal standard method. Results： Three target substances had a good linear relationship in the range of 0.1~20.0 ng/mL, and the correlation coefficient was greater than 0.999 46. The detection limit and quantitative limit were 0.1~0.2 μg/kg and 0.2~0.7 μg/kg, respectively. Average recoveries at three spiked levels in the coffee matrix were 79.0%~103.3% with a relative standard deviation of 1.5%~7.6%. Conclusion： This method has the advantages of simple sample pretreatment, good reproducibility and high efficiency, and is suitable for the high-throughput detection of multiple ochratoxins in different coffee samples.