Determination of aflatoxin B1, B2, G1, G2 in cashew nut by UHPLC-HRMS

Abstract

In recent years, Vietnam is the leading country in exporting cashew to global market. However, tropical climate is a significantly favorable condition for fungus to develop when the cashew is not properly stored. For this reason, mycotoxin contaminations are likely to occur on the cashew, especially aflatoxin. By utilizing solid phase extraction technique with Oasis HLB stationary phase and optimizing conditions of sample preparation, the toxins such as aflatoxin B1, B2, G1 and G2 were extracted and concentrated from cashew samples. Simultaneously, with the assistance of ultra high-performance liquid chromatography coupled with high resolution mass spectrometry detector, this study has successfully fabricated concurrent analysis method of aflatoxin compounds with high sensitivity and selectivity. The method established in this study manifested a high linear range (R2 ≥ 0.995), sensitivity (limits of detection ranged from 0.05 to 0.10 μg/kg and limits of quantification varied from 0.5 to 1.0 μg/kg), adequate recovery (96.5-109.4 %), and good repeatability (intra-day precision in the range of 2.2-6.1 % and inter-day precision in the range of 3.6-13.3 %). In particular, this method has been successfully applied for the determination of 4 aflatoxins in real cashew nut samples.