Ion-mo bility spectr ometry as a fast monitor of

Ion-mobi lity spectrome try (IMS) has been know n best for screening explos ives at airports , detecting chem ical agen ts fo r the military, and monitor ing stack gas emissi ons in industry. Th ese have been suppleme nted by ap plications for determi ning the accumu lation of impurit ies in gas switch es for hydroe lectric generat ing stat ions and fo r measur ing the levels of volatile org anic compoun ds in the life- suppor ting atmosp here of the Intern ational Space Station . An enlarged scope of applicati ons for th is fast method has become possible throug h advan ces in miniat urization of drift tubes a nd new methods for character izing ions. Also, ion sources of broa d impo rtance, such a s elect rospray ionization , have been add ed to drift tubes at ambien t pres sure. Finall y, the ion chem istry, which long made IMS a sensit ive and selective sensor but al so frustra ted attempts to ration alize respo nse, has been explore d and clarifi ed. New methods for intr oducing struc-tural conten t into mobility spectra mean th at mobi-lity spe ctromete rs can be general analyti cal measu rement devices and can prov ide ra pid analys is of samp les spann ing the range of vapor pressures and chem ical classes. Th is article pres ents sel ected recent developm ents in IMS with emphasi s on speed of measu rement or on uses for which no other method has been con venient or econom ical.