MASS ANALYZERS

This chapter discusses the advantages and disadvantages of the most widely used mass analyzers, including those employed in single- and double-focusing magnetic deflection instruments, time-of-flight (TOF) instruments, and quadrupole instruments. In addition, the different methods of scanning the analyzers to extend their range of applicability are discussed. The choice of a mass analyzer depends on a number of interrelated factors, such as (i) mass range (maximum m/z detectable); (ii) resolving power (ability to separate ions of closely similar m/z); (iii) accuracy of mass measurement (useful only if ions are completely resolved from interfering ions); (iv) ion transmission, sensitivity, and Q value (“figure of merit” for a mass analyzer); (v) scanning speed [usually quoted as time taken to scan a decade in mass (e.g., m/z I000 → m/z 100)]; and (vi) ease of use with ancillary equipment (such as chromatographic equipment). No mass analyzer is suitable for all applications and the choice of instrument is determined by the type of problem under investigation. © 1990, Elsevier Inc. All rights reserved.