Simultaneous determination of 37 mycotoxins in grain and animal feed by impurity adsorption purification coupled with ultra-performance liquid chromatography-tandem mass spectrometry

Abstract

A rapid method based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of 37 mycotoxins having various physicochemical properties in grain and animal feed samples. The 37 analytes were extracted from ground samples with acetonitrile-water-formic acid (84:15.9:0.1, v/v/v) by 20 min vibration, and purified using a commercial MLJ-1 pass-through solid-phase extraction (SPE) clean-up cartridge. The analytes were then separated on a reversed-phase BEH RP18 column by a gradient elution program with 0.1 mmol/L ammonium acetate (containing 0.1% (v/v) formic acid) aqueous solution and 0.1% (v/v) formic acid methanol solution as mobile phases. The separated analytes were detected by MS/MS in the multiple reaction monitoring (MRM) mode via ESI+/- ionization. The results showed that the purification was completed in 1 min and that the 37 analytes could be separated on the chromatographic column in 15 min. The 37 mycotoxins showed a linear relationship within their respective linear ranges, and the correlation coefficients of the matrix-matched calibration curves were greater than 0.98. The average recoveries at four spiked levels (limit of quantification (LOQ), LOQ×5, LOQ×10, LOQ×25) for all the targets except fumonisins ranged from 80% to 120%, with the relative standard deviations (RSDs) lower than 20% (n=6). The limits of quantification (LOQs) for all the analytes were between 2 and 40 μg/kg. The proposed method is simple, fast, and accurate, thus being suitable for detecting multiple mycotoxins in grain and animal feed samples.