Detection of Trace Concentration of Explosives on Human Fingers and Documents Using Ion Mobility Spectroscopy

The sampling unit of the device, based on ion mobility spectroscopy technique, for detection of ultra-small concentration of substances on human fingers and documents, is described. The vapor pressure of some substances is subtle; so the heating of an examined surface is a must for efficient detection of these substances. In the present work it was shown (by the thermal transfer investigation) that more efficient method of surface heating consists of the using of the impulse gas-discharge lamp in comparison with the use of a heated air flow or heat transfer from the warm body by thermal conductivity. However the heating of the human fingers by the irradiation of the gas-discharge lamp is not effective because of a small concentration of the melamine (pigment of the black or brown color) in the skin of the human palm. Therefore in this work the combination of the two methods is used: irradiation of the gas-discharge lamp heats grid and a grid heat the surface of the finger that is pressed to a grid. The system will be effective for the control of admission to public events and providing anti-terrorist measures (1-3).