Detection performance of a portable ion mobility spectrometer with 63Ni radioactive ionization for chemical warfare agents

The detection performance of a portable ion mobility spectrometer (IMS) (SABRE 4000, Smiths Detection) with Ni-63 ionization, air purification, and reduced ion mobility measurements using calibrants was investigated for vapors of chemical warfare agents. In a matter of several seconds, the SABRE 4000 enabled tentative identification of sarin, soman, cyclohexylsarin, tabun, and nitrogen mustard 3, each with a limit of alarm (LOA) of 0.005-0.5 mg m(-3) in positive ion collection mode. Hydrogen cyanide could be identified with a LOA of 0.2 mg m(-3) in the negative mode. Mustard gas, nitrogen mustards 1, 2, and 3, phosgene, and chloropicrin showed a positive alarm of "HD/Phos" with a LOA of 0.2-2 mg m(-3) in negative mode. Lewisite 1, cyanogen chloride, and chlorine vapors did not show any alarm, although the characteristic ion peaks appeared in negative mode. The peak areas of the respective detected ions on the second differentiation spectra were positively correlated with the corresponding vapor concentrations in low concentration ranges. Several chemical agent simulants and organic solvents were also examined for detection by the machine. The SABRE 4000 is superior to other portable IMS machines at this time, although some improvements of the system are necessary.