CIRCLE CELL FT-IR ANALYSIS OF CHEMICAL WARFARE AGENTS IN AQUEOUS-SOLUTIONS

The qualitative and quantitative FT-IR analyses of dilute aqueous solutions of the chemical warfare threat agents tabun (GA), sarin (GB), and soman (GD) were evaluated with the use of the CIRCLE CELL. Infrared spectra were recorded with a Nicolet 60SXB FT-IR spectrometer fitted with a liquid-nitrogen-cooled MCT-A detector. The CIRCLE CELL used a modified micro, high-pressure, flow-through sampling accessory fitted with a ZnSe internal reflection element. Peak heights were evaluated with the Nicolet SUPER QUANT program after spectral subtraction of the solvent. The P=O stretching absorption band, centered around 1240 cm-1, produced good quantification in the concentration range 0.5 to 2.0 mg/Ml. In this concentration range the intra-daily precision had a percent coefficient of variation (% CV) of less than 3.0%, while the inter-daily precision yielded a % CV of less than 6.0%. The detection limit was observed to be 0.3 mg/mL for GA and 0.2 mg/mL for GB and GD.