Identification of Individual Mycotoxin Threat Agents from Mycotoxin Mixtures Using Nuclear Magnetic Resonance, Mass Spectroscopy, and Chemometrics

摘要

The U. S. government still claims that the Soviet Union and its allies in Laos and Cambodia used a mixture of mycotoxins to engage in toxin warfare from 1975 to 1984. While the government's case for toxin warfare is suspect Tucker, J. B. (2001) The Nonproliferation Review, mycotoxin mixtures are potent enough to be considered threat agents. Therefore, the need exists for the capability to identify individual toxins from mixtures. We are investigating techniques to accurately and efficiently identify specific mycotoxins from mixtures of mycotoxins using NMR, MS, and chemometrics. We used LC-MS and 2D NMR to identify aflatoxins G1, G2, B1 and B2 in mixtures based on fingerprint spectral regions. Either method is reasonably efficient for mixtures containing few components. However, the higher the structural similarity between toxins and/or the increased number of components in a mixture, the more cumbersome the task becomes. We explored chemometrics as a means to overcome this inherent difficulty by carrying out a preliminary analysis using chemometrics in combination with 1D 1H NMR. Chemometrics allowed accurate identification of individual aflatoxins G1, G2 and B2 from a mixture of the three without requiring 2D experiments. Also, for samples containing a contaminant (with similar molecular weight to aflatoxins), the analysis flagged these samples as containing an 'unknown' component. This work shows that chemometrics combined with NMR and/or MS is promising as a robust solution to the identification of threat toxins from complex mixtures.