Stability of Dilute Tabun (GA) Solutions in Various Vehicles

摘要

Tabun (GA) is unstable in aqueous media, which has created difficulties in supplying reliable preparations of GA in saline for toxicity studies. We previously demonstrated the stability of GA in Multisol (M), a four- component solvent (48.5% H2O, 40% propylene glycol, 10% ethanol, and 1.5% benzyl alcohol) used in various chemical preparations. However, M's 10% ethanol content may alter toxicity findings. We used 31P nuclear magnetic resonance (P- NMR) and gas chromatography mass spectrometry (GCMS) to investigate the stability of GA in two modifications of M. Mixture No. 1 contained 48.5% D2O, 45% propylene glycol, 5% ethanol, and 1.5% benzyl alcohol; No. 2 contained 48.5% D2O, 50% propylene glycol, and 1.5% benzyl alcohol. Using P-NMR we found GA to be stable for approximately 3 h at 25 deg C in both mixtures. Using GCMS we found that GA was stable in both mixtures at -70 C for more than 14 months. We performed separate dilutions of GA in mixture No. 1, mixture No. 2, and the original M with saline prepared with D2O; we monitored GA's stability. Using P-NMR we demonstrated GA's stability at 25 C for approximately 9 h in the dilutions of both mixtures and for at least 3 h in the original M dilution. This work demonstrated that the reduction or removal of ethanol from M can be accomplished without unduly influencing GA's stability for researchers and provides the length of time of GA's stability when diluting M vehicles with saline prepared with D2O at 25 deg C. These vehicle modifications may be helpful in future GA toxicity studies.