ABSTRACT
Advances in methods to introduce samples into ion mobility spectrometry (IMS) drift tubes as described in Chapter 3 have enabled the range of applications of IMS to be expanded beyond the measurements of gases, vapors, and volatile and semivolatile compounds normally associated with IMS. Molecules and samples, wholly new to IMS measurements, such as peptides, proteins, and carbohydrates, have been explored during the past decade and may have importance in medical research or clinical use. Such studies have been made possible in large part through the adaptation of methods of sample delivery and ionization that have been successfully pioneered in mass spectrometry (MS) during the past 20 years. These include electrospray ionization (ESI) and nano-ESI for aqueous samples or matrix-assisted laser desorption ionization (MALDI) for solid samples as discussed in Chapter 3. The importance of these methods in chemical sciences was recognized with the award of the 2002 Nobel Prize in Chemistry to John B. Fenn1 and Koichi Tanaka2 for developing ESI and MALDI, respectively. In some cases, IMSs may replace MSs in simple biological investigations; in other cases, the mobility spectrometer may serve as a lter for removing interferences in MS measurements or even afford some mode of separating isomeric ions and obtaining structural information. These systems are sometimes referred to as ion mobility-mass spectrometry (IM-MS), and several variations have been used for laboratory studies of macromolecules (see Chapter 9). Compared with MS, mobility spectrometers are inexpensive, portable, and sensitive analyzers that use low power. What may be compromised in density of information in comparison to a MS is rewarded with savings in cost and convenience.
