TANDEM MASS-SPECTROMETRY - QUADRUPOLE AND HYBRID INSTRUMENTS

This chapter discusses quadrupole and hybrid instruments of tandem mass spectrometry. The general concept of tandem mass spectrometry (MS/MS) as a tool that delineates connectivity relationships between precursor and product ions are reviewed briefly in the chapter. The present chapter is mainly concerned with instruments, designed specifically for experiments of this type, which use quadrupole mass filters as analyzers for the product ion(s) finally detected in the experiment. The precursor ion analyzer is most frequently another quadrupole (the triple quadrupole instruments), but an increasing number of tandem instruments incorporate a sector analyzer as the first stage; such “hybrid” instruments combine the high-mass/high-resolution advantages of the modern sector instrument with the flexibility of the quadrupole. The present chapter contains four main sections. The first two of these cover material (general concepts of tandem mass spectrometry and operational properties of rf-only quadrupoles) pertinent to both kinds of XqQ instruments. Each of the two remaining sections is devoted to one of these two types, their special advantages and problems, and is illustrated, where appropriate, by examples from the recent literature. The chapter concludes with a summary and discussion of future directions. © 1990, Elsevier Inc. All rights reserved.