Ion Mobility Spectrometry in Forensic Science

Abstract

AbstractIon mobility spectrometry (IMS) is an analytical technique that has primarily been used as a trace chemical monitor in the field. The benefits of IMS as a field detector are its simplicity, sensitivity, fast analysis times, portability, ruggedness, and its operation at ambient pressures. IMS has successfully been used for many years to detect traces of explosives at airports and other security checkpoints; illicit drugs in prisons, cargo, and in border security. The military have long used IMS for detection of chemical warfare agents. Innovations in drift tubes, nonradioactive ion sources, and hyphenated IMS techniques in recent years have expanded the range of forensic applications. A sample introduced into the IMS undergoes atmospheric pressure chemical ionization and the resulting product ions are separated by their mobilities in the drift tube. Several factors such as temperature, humidity, concentration and presence of interferences can affect the ionization and separation process. This article describes the principles of IMS, developments in technology, and their implications for forensic science. IMS trends in detection of explosives, illicit drugs, and chemical warfare agents are discussed. The article also provides an overview of some unconventional applications and some interesting emerging forensic applications of IMS.