Simultaneous determination of four aflatoxins and ochratoxin A in ginger after inoculation with fungi by ultra-fast liquid chromatography-tandem mass spectrometry.

Abstract

Aflatoxins (AFs) and ochratoxin A (OTA) have been detected frequently in food, agricultural products and traditional Chinese medicines, and their presence poses serious health and economic problems worldwide. Ginger can easily be polluted with mycotoxins. In this study, ginger samples were cultivated for 15 days after inoculation with fungi and were prepared based on ultrasound-assisted solid-liquid extraction using methanol/water followed by immunoaffinity column clean-up and analysed by ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) for AFs and OTA. The limits of detection and quantification of AFs and OTA were 0.04-0.30 µg mL(-1) and 0.125-1.0 µg mL(-1) , respectively. The recoveries were 82.0-100.2%. After 15 days' cultivation, no macroscopic mildew was found in ginger. But, the content of AFB1 expressed an increasing trend in ginger, peel [less than the limit of quantification (LOQ)] to the innermost layer (51.86 µ mL(-1) ), AFB2 was only detected in the innermost layer at the level of 0.87 µ mL(-1) . A small amount (<LOQ) of OTA was found in the peel of ginger after the two fungi were inoculated on the surface of ginger. The developed method was successfully applied to analyse five mycotoxins, and has many advantages including rapid determination and high sensitivity. Meanwhile, in practice, more attention should be paid to the safety and quality of ginger. © 2016 Society of Chemical Industry.