Identification of the bright-greenish-yellow-fluorescence (BGY-F) compound on cotton lint associated with aflatoxin contamination in cottonseed

In order to characterize the structure of the bright-greenish-yellow-fluorescence (BGY-F) compound on cotton lint associated with aflatoxin contamination in cotton seed, various in vitro and in vivo natural BGY-F reaction products were prepared. Under similar high pressure liquid chromatography separation with variable wavelength and programmable fluorescence detection (HPLC-UV/FL), combined with atmospheric pressure ionization and mass spectral determinations it was found that the BGY-F reaction products prepared from three preparations: (a) kojic acid (KA) + peroxidase (soybean peroxide or horseradish type VI and type II) + H2O2, or (b) detached fresh cotton locules + KA + H2O2, or (c) attached field cotton locules that were treated with a spore suspension of aflatoxigenic Aspergillus flavus, all resulted in identical chromatographic characteristics, and all exhibited a molecular weight of 282. Further characterization of the BGY-F reaction product with 1H- and 13C-NMR spectroscopic analysis revealed that it was a dehydrogenator dimer of 2 KA, linked through the C-6 positions.