A chemical vapor detector/monitor you can hold in the palm of your hand. A miniature ion mobility spectrometer

Ion Mobility Spectrometry (IMS) has progressed over the past 30 years from a laboratory curiosity to laboratory instrumentation to hand-held chemical vapor detectors or monitors. The main advantages of an IMS device are that it will operate at atmospheric pressure, it offers low picogram limits of detection because of efficient atmospheric pressure chemical ionization processes, it is relatively compact, it uses relatively little electrical power, and its selectivity can be governed by chemical control of ion-molecule reactions. A hand-held version of IMS-based equipment is a part of the chemical defense equipment inventories in most countries throughout the free world. That equipment weighs 2.2 kilograms. A prototype Miniature IMS device (Mini-IMS) weighs about 700 grams (including batteries) and will fit in the palm of a human hand. The current Mini-IMS device consumes about 1.5 watts of power on a continuous basis; future units will be designed to consume less than one watt. Typical IMS utilizes flowing gases, scrubbed with charcoal and/or molecular sieves, into which sample vapors are mixed. Air pumps required to move these gases are major consumers of electrical power. In the Mini-IRIS concept, no such pumps are involved. A periodic burst of sample-laden air, effected by the motion of a small loudspeaker, is ingested into the Mini-IMS device by an operator or under computer control, "sample on demand." Other than the loudspeaker no moving parts are required. Molecular sieves are used to scrub internal air of sample and background materials; the scrubbing process continues, by diffusion, even when the device is turned off. Experimentally determined response characteristics of the Mini-IMS device, sensitivity, response time and recovery time, will be described for applications including detecting and monitoring organophosphorus compounds, aromatic esters, chlorinated sulfides and some complex ethers in the atmosphere. Sensitivity of Mini-IMS is comparable to existing field IMS systems, response and recovery times are considerably faster, and the dynamic range for response is more than an order of magnitude greater.