Simple sample preparation for analysis of mycotoxin residues in rice

Abstract

A new non-immunoassay based extraction method for aflatoxin B1, B2, G1, and G2, fumonisin B1 and B2, ochratoxin A and B, citrinin, deoxynivalenol, nivalenol, HT-2 toxin, T-2 toxin and zearalenone was developed for mycotoxins screening in rice. The association of ultra performance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS) was used to determine the all mycotoxins via electrospray ionization in ESI+ and ES- and multiple reaction monitoring (MRM) for the operating mode of analysis. Mycotoxins were isolated by acquity UPLC BEH C18 column (100 mm x 2.1 mm, 1.7 µm) with 0.5% formic acid in 5 mM ammonium formate/(acetonitrile in methanol = 1:1) by gradient elution within 11 minutes. Modified QuEChERS method employed 10% (v/v) formic acid in acetonitrile for solvent extraction. Cleanup was done by dispersive (d-SPE) combination of PSA, C18 and neutral alumina. The linear regression was evaluated by matrix-matched calibration from 0.01-0.1 mg/L and 0.05-2.5 mg/L, acceptable linearity with all R2 values better than 0.99 were obtained. Percentage of recovery ranged from 53 to 104 with within-day and between-day precisions at three concentration levels (low, middle, high) showed %RSD values lower than 7.1% and 11.8% (n=10), respectively. The limits of detection range were calculated by 3 times of signal to noise (3S/N). The proficiency testing was served with Z-score in the satisfactory range. This method is effective and rapid, and fit for purpose to replace expensive import immunoaffinity columns and possibly employed in routine analysis of mycotoxins residues in several grains.