ABSTRACT
Ion mobility spectrometry (IMS) arose from discoveries of the formation and behavior of ions in air and other gases at ambient pressure and from an interest in exploring the chemistry and properties of electrical discharges in gases. These were strongly linked to studies on lightning that began in the late 1700s1 and to interests in the electricity throughout the 1800s.2 Certain aspects of this history can still be seen today in IMS technology with corona discharges as ion sources. Similarly, ion-molecule reactions that occur in the troposphere can be associated with the chemical reactions that occur in a mobility spectrometer at ambient pressure. IMS has passed through decades of study in government, industry, and academic laboratories and applications in military establishments and commercial aviation security. Today, ion mobility spectrometers remain a preferred solution in these same venues, offering high speed, durability, and reliability. The attractive features of IMS methods for biomolecule measurements, providing details on molecular size and shape in addition to mass, have motivated the present period of vigorous innovation, expanded commercialization, and growing breadth of applications. Four major stages of development for IMS can be recognized, and each is described separately here.
