Biotoxin activity assays typically involve multistep sample preparation, multicomponent reactions, multistep analysis, or a combination thereof. We report a single-step, real-time ricin activity assay that requires little or no sample preparation and employs direct analysis in real time mass spectrometry. The release of adenine from the inhomogeneous substrate herring sperm DNA by ricin was determined to be 53 +/- 2 pmol adenine per picomole of ricin per hour. This procedure can be readily adapted to any enzyme for which a reactant or product of low molecular weight (up to approximately 600) can be identified.

A theoretical study of the decomposition pathways of 1,3,3-trinitroazetidine (TNAZ) is described. Possible decomposition transition-states, intermediates, and products are identified and structures, energies, and vibrational frequencies are determined at the B3LYP/6-31G(d,p) level for these species. Four major pathways are apparent. Two pathways are initiated by the fission of the N–NO2 and C–NO2 bonds to yield radical intermediates, while the other two pathways involve the molecular elimination of HONO. Energy profiles for the pathways and possible routes to some of the experimentally observed species of TNAZ decomposition are presented. The energy required to initiate the NO2 bond fission pathways are 4–8 kcal/mol lower than the HONO elimination pathways. In the gas phase, the NO2 elimination pathways will be the dominant routes for TNAZ decomposition. In the condensed phase, however, this trend may be reversed.

Development of a rapid field test is needed capable of determining if field supplies of water are safe to drink by the warfighter during a military operation. The present study sought to assess the effectiveness of handheld assays (HHAs) in detecting ricin and Staphylococcal Enterotoxin B (SEB) in water. Performance of HHAs was evaluated in formulated tap water with and without chlorine, reverse osmosis water (RO) with chlorine, and RO with bromine. Each matrix was prepared, spiked with ricin or SEB at multiple concentrations, and then loaded onto HHAs. HHAs were allowed to develop and then read visually. Limits of detection (LOD) were determined for all HHAs in each water type. Both ricin and SEB were detected by HHAs in formulated tap water at or below the suggested health effect levels of 455 ng/mL and 4.55 ng/mL, respectively. However, in brominated or chlorinated waters, LODs for SEB increased to approximately 2,500 ng/mL. LODs for ricin increased in chlorinated water, but still remained below the suggested health effect level. In brominated water, the LOD for ricin increased to approximately 2,500 ng/mL. In conclusion, the HHAs tested were less effective at detecting ricin and SEB in disinfected water, as currently configured.

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