Development and optimization of a method based on QuEChERS-dSPE followed by UPLC-MS/MS for the simultaneous determination of 21 mycotoxins in nutmeg and related products

Abstract

Nutmeg (Myristica fragrans), a popular spice and traditional medicine worldwide, is susceptible to fungal and mycotoxin contamination. Hence, it is important to monitor the residual levels of multiple mycotoxins in nutmeg and related products. However, analysts are continuously faced with the challenges of quantifying mycotoxin concentrations in complex matrices such as spices and traditional Chinese medicines. To develop a simple and sensitive mycotoxin analysis method encompassing the total workflow from sample preparation to quantitative analysis, a simple, robust, and sensitive method for the simultaneous identification and quantification of 21 mycotoxins in nutmeg and related products was described. The method is based on sample preparation by modified QuEChERS extraction and dispersive solid-phase extraction (dSPE) cleanup followed by ultrahigh-performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-MS/MS). Matrix-matched calibration was applied for the quantification of the investigated mycotoxins. The limits of detection of the target analytes ranged from 0.04 μg/kg to 6.0 μg/kg. Recovery rates ranged from 60.49% to 97.46% at three spiking levels, with relative standard deviations<13%. This method was applied to 45 samples of nutmegs, mace and related products. Three nutmeg samples and one nutmeg powder were contaminated with aflatoxins with residue levels of 1.76 ~ 3.39 μg/kg for AFB1 and 2.51 ~ 8.77 μg/kg for AFs (the sum of AFB1, AFB2, AFG1, AFG2 and AFM1). No mycotoxins were detected in mace. All of the contamination levels were below the regulatory maximum residue limits suggested by the European Commission and China.