ABSTRACT
The performance of an ion mobility spectrometer and consequently the results from a measurement depend on choices of design and fabrication of each component in the instrument, including the sample inlet, ion source, ion injector, mobility method for the drift tube, dimensions of the drift tube, detector characteristics, and speed of electronics, including parameters of signal processing. While these are controllable with research-grade instruments, they are commonly pre-determined with commercial instruments and are not easily altered by the operator. Measurements with all ion mobility instruments are affected signicantly by experimental parameters, including the chemical composition of the drift gas, levels of moisture of the supporting atmosphere inside the drift tube, temperature of this same gas, and any intentional or unintentional change in the identity of reactant ions. All of these are controllable, in principle, with laboratory-and research-grade instruments, and some, such as temperature and drift gas moisture, may be controlled with commercial instruments. As a rule, experimental parameters for handheld mobility analyzers are in§exible apart from moisture and gas purity, which are controlled by onboard and exchangeable gas purication lters.
