IDENTIFICATION OF TEAR GASES IN SUSPECT SPRAY CANS AND CLOTH SAMPLES BY ION MOBILITY SPECTROMETRY

A handheld ion mobility spectrometer was used to characterize the vapo rs produced at 50 degrees C by the active ingredients of 20 mu L sampl es of commercially available CN and CS tear gas sprays. After separati on of the active ingredients of the sprays from their carrier gases an d solvents, the spectra obtained are indistinguishable from standards, and can be used as vapor phase ''fingerprints'' to distinguish betwee n these tear gas agents. The evaporative method used to separate the a ctive ingredients from propellants and solvents was simple, but very e ffective in removing spectral interferences. We suggest that from the perspectives of speed of response, portability, intrinsic low detectio n limits, and the secondary information available from ion mobility sp ectra, these studies illustrate the potential of mobility spectrometry to fulfill forensic requirements for a rapid screening method for sus pect spray cans and clothing.