Ion mobility mass spectrometers

Ion mobility (IM) mass spectrometers are hybrid instruments that combine an IM separation system with conventional MS systems. An ion mobility spectrometer (IMS) can also serve as a stand-alone ion detection system [72]. An IMS uses gas-phase mobility rather than the m q ratio as a criterion to separate ions [73,74]. The mobility of ions is measured under the influence of an electrical field gradient and cross-flow of a buffer gas, and depends on ion s collision cross section and net charge. 

The resolution of an IMS, nsnally very low (10 to 12) can be increased to 200 to 400 by increasing the pressnre of the buffer gas, connecting the ion source directly with the drift tube, increasing the length of the drift tube, and increasing the electric field gradient of the drift tube. Unlike LC/MS separation, an ion chromatogram can be obtained within 1 s. 

Other applications of IM-MS include the detection of drugs, chemical warfare agents, and environmental pollutants size distribution of aerosol particles structure information of gas-phase clusters and conformational studies of proteins and oligonncleotides [79], 

A variation of IMS is field-ion spectrometry (FIS), which functions as an ion filter to allow one type of ion to be transmitted continuously [80], In FIS the 

---

Recently, the new kinetic ion mobility mass spectrometer (KIMMS) was used to determine the rate constants for the SN2 reactions of a distribution of chloride cluster ions, Cr(CHCl3)o 2, with MeBr and Mel in N2 buffer gas at atmospheric pressure232. 

The already-mentioned kinetic ion mobility mass spectrometer (KIMMS)307 was also used to determine equilibrium constants for the clustering reactions of equation 36 at 1 atmosphere of pressure. 

Sundarapandian, S. May, J.C. McLean, J.A., Dual source ion mobility-mass spectrometer for direct comparison of electrospray ionization and MALDI coUision cross section measurements. Anal. Chem. 2010, 82, 3247-3254. 

FIGURE 9.6 Schematic of a traveling wave ion mobility-mass spectrometer. (Available at http //pubs.acs.org/cen/coverstory/86/8637cover.html/. With permission.)... 

May, J.C. Russell, D.H., A mass-selective variable-temperature drift tube ion mobility-mass spectrometer for temperature dependent ion mobility studies, J. Am. Soc. Mass Spectrom. 2011, 22(7),1134-1145. 

Williams, J.P. Scrivens, J.H. Coupling desorption electrospray ionization and neutral desorption/extractive electrospray ionization with a travelling-wave based ion mobility mass spectrometer for the analysis of drugs. Rapid Commun. Mass Spectrom. 2008, 22, 187-196. 

Giles, K. Grimsrud, E.P. The kinetic ion mobility mass spectrometer Measurements of ion/molecule reaction rate constants at atmospheric pressure. J. Phys. Chem. 1992, 96, 6680-6687. 

This research was supported by the Intramural Research Program of the National Institute on Drug Abuse, NIH. The authors thank the Office of National Drug Control Policy (ONDCP) for instrumentation funding, without which this and other projects could not have been accomplished and Dr. J Albert Schultz and Tom Egan (lonwerks, Inc.) for assistance with the ion mobility mass spectrometer and the imaging computer software. 

Ion mobility-mass spectrometers are composed of an ion source, a mobility separation cell, a mass analyzer, and a detector as depicted in Fig. 21.1a. There are many variations to the general... 

Fjeldsted, J.C. and McLean, J.A. (2014) Conformational ordering of biomolecules in the gas phase Nitrogen collision cross sections measured on a prototype high resolution drift tube ion mobility-mass spectrometer. Anal. Chem. 86, 2107-2116. 

Temperature Ion Mobility Mass Spectrometer for Improved Ion Mobility Resolution... 

FIGURE 6.3 A schematic of the mass selected, cryogenic ion mobility-mass spectrometer with the important components labeled. Representative operational base pressures are provided in the lower bar. Components are to scale. 

Femandez-Lima, F. A., C. Becker, K. J. Ghlig, et al. 2008. Ion mobility-mass spectrometer interface for cohisional activation of mobihty separated ions. Anal. Chem. 81 618-24. 

Many metabolites are polar, ionic, and nonvolatile. Thus comprehensive metabolic analysis is not well suited for gas chromatographic techniques. Metabolite mixtures in complex biological samples such as lymph and blood, however, can be rapidly characterized by electrospray ionization with ion mobility coupled to mass spectrometry. As with GC-IMS, coupling ion mobility spectrometers with mass spectrometers produces two dimensions of information. There are many types of ion mobility-mass spectrometers (IM-MS) and most of these will be discussed in other chapters of this book. The focus of this chapter, however, is on atmospheric pressure IMS with quadrupole or time-of-flight mass spectrometry. Other types of IM-MS have also been recently been reviewed. Advantages of coupling atmospheric pressure IMS with a mass spectrometer include ... 

Wyttenbach, T. Kemper, P. R. Bowers, M. T. Design of anew electrospray ion mobility mass spectrometer. International Journal of Mass Spectrometry 2001, 212, 13-23. 

After presenting an overview chapter and the fundamentals, the book focuses on instrumentation and ionization sources. It describes an ion-mobility-capable quadrupole time-of-flight mass spectrometer, the differential mobility analyzer, a cryogenic-temperature ion mobility mass spectrometer, the atmospheric solids analysis probe method, and laserspray ionization. In the final applications-oriented chapters, the contributors explore how homebuilt and commercial instruments using electrospray ionization and matrix-assisted laser desorption/ionization (MALDl) methods are employed to solve biological and synthetic issues. 

---