Accurate Identification of Degraded Products of Aflatoxin B1 Under UV Irradiation Based on UPLC-Q-TOF-MS/MS and NMR Analysis

Abstract

Analysis, purification, and characterization of AFB1 degraded products are vital steps for elucidation of the photocatalytic mechanism. In this report, the UPLC-Q-TOF-MS/MS technique was first coupled with purification and NMR spectral approaches to analyze and characterize degraded products of AFB1 photocatalyzed under UV irradiation. A total of seventeen degraded products were characterized based on the UPLC-Q-TOF-MS/MS analysis, in which seven ones (1–7) including four (stereo) isomers (1,2, 5, and 6) were purified and elucidated by NMR experiments. According to the structural features of AFB1 and degraded products (1–7), the possible photocatalytic mechanisms were suggested. Furthermore, AFB1 and degraded products (1–7) were evaluated against different cell lines. The results indicated that the UPLC-Q-TOF-MS/MS technique combined with purification, NMR spectral experiments, and biological tests was an applicable integrated approach for analysis, characterization, and toxic evaluation of degraded products of AFB1, which could be used to evaluate other mycotoxin degradation processes.

UV light treatment (278 nm) for detoxification of aflatoxins and application in edible and medicinal herb coix seed

“…Looking back on AFs over the past few years, several articles have summarised and related to UV technology in the reduction of AFB 1 (Wang et al, 2021(Wang et al, , 2022bKumar et al, 2022). There is still a gap with regard to the possible irradiation mechanism and toxic evaluation of AFB 2 and AFG 1 .…”

“…In particular, AFB 2 without C 8 ‐C 9 double bond structure are more sensitive to ultraviolet radiation (Peng et al ., 2023). On the basis of previously reported photodegradation mechanisms of AFB 1 , the relationship between AFG 1 , AFB 2 and their degradation products was further elucidated (Kumar et al ., 2022; Velazhahan et al ., 2010; Wang et al ., 2021). Firstly, ultraviolet radiation could cause the formation of reactive hydroxyl (OH • ), hydrated electrons (eaq−), hydrogen atoms (H • ) and methoxy species (OCH 3 •) when methanol–H 2 O was irradiated with UV.…”

Synergistic Adsorption–Photocatalysis based on Magnetic Metal–Organic Framework Nanoplatforms for Organic Pollutant Removal

“…Furthermore, based on the free radical reactions, ring cleavage reactions occurred in the bi-furan ring and coumarin skeleton of AFB1. AFB1 is the most potent toxicity among aflatoxins, and the C8C9 double bond at the end of the furan ring in its structure is the key toxic group; when this site is broken, the toxicity of AFB1 will be reduced substantially . Based on the structure–activity relationship and structures of the degradation products in this study, it can be judged that the photocatalytic elimination of the toxic site of AFB1 can effectively reduce its harmfulness.…”

“…To verify that photocatalysis based on magnetic catalysts could degrade AFB1 to yield detoxified products, the UPLC-ESI-MS spectra for the degraded products of AFB1 were measured (Figure S8). According to the different molecular weights determined by UPLC/MS, we identified the structures of the products by comparing them with the existing database established in our previous study 35 and speculated on the transformation pathway of AFB1 in the photocatalytic process (Figure 5). Clearly, Fe 3 O 4 @UiO-66-based photocatalysis first breaks the double bond of the toxin, which is consistent with the mechanism of the free radical addition reaction.…”