Degradation of aflatoxin B1 by low-temperature radio frequency plasma and degradation product elucidation

Plasma is a partially ionized gas that contains abundant free radicals and UV photons. In this work, the application of low-temperature radio frequency plasma in aflatoxin B1 (AFB1) degradation was investigated and the possible structures of the degradation products were elucidated. It was revealed that AFB1 could be effectively degraded by plasma and exposure to 300 W plasma for 10 min resulted in a degradation rate of up to 88.3 %. Kinetic analysis showed that the degradation process followed a first-order reaction and the generator power was the dominative parameter for AFB1 decomposition. Five major compounds, including 3-(hydromethyl)-8, 9-dihydro-2H-furo[2, 3-h]chromen-8-ol, 1-hydroxy-2-oxo-5-(2, 4, 6-trihydroxy-2, 3, 3a, 8a-tetrahydrofuro[2, 3-b]benzofuran-5-yl)cyclopentanecarboxylic acid, 2-(2, 4-dihydroxy-2, 3, 3a, 8a-tetrahydrofuro[2, 3-b]benzofuran-5-yl)-5-hydroxycyclopent-1-enecarboxylic acid, 1-hydroxy-2-(4-hydroxy-6-methoxy-2-oxo-2, 3, 3a, 8a-tetrahydrofuro[2, 3-b]benzofuran-5-yl)-5-oxocyclopentanecarboxylic acid, and 1, 2-dihydroxy-5-(4-hydroxy-2-oxo-2, 3, 3a, 8a-tetrahydrofuro[2, 3-b]benzofuran-5-yl)cyclopentanecarboxylic acid, were revolved and identified from the degradation product by using UPLC–Q-TOP–MS, and the addition reaction was mainly responsible for AFB1 decomposition. All the five degradation products lost their double bonds in the terminal furan ring and hence theoretically had reduced toxicity compared with AFB1 according to the structure–activity relationship. For this reason, the low-temperature radio frequency plasma is proposed potential in the decontamination of AFB1.