The presence of trace molecules in air is often determined using a
well-known device called an ion mobility spectrometer. Such devices are
commonly utilized in the fields of explosives detection, identification of
narcotics, and in applications characterized by the presence of very low
airborne concentrations of organic molecules of special interest. The
sensitivity of such instruments is dependent on the method of gas sampling
utilized. The vortex sampling nozzle consists of an intake gas flow and a
separate coaxial heated, emitted gas flow that is deflected to move with a
circular motion. A heated vortex sampling nozzle can greatly improve the
sampling efficiency for low volatility target molecules, particularly when
the sampling needs to be performed at a distance from the air intake and
the vapor pressure of the target molecules is very low. Additionally, the
vortex air may contain one or more additional substances that promote
vaporization, combine with the target molecule, or provide a known marker
in the ion mobility time-of-flight spectrum.
