Tandem Mass Spectrometry of Nucleic Acids

Tandem mass spectrometry, also termed MS/MS, refers to any mass spectrometric method that involves at least two stages of mass analysis.1 The most generally implemented scheme involves the following: (1) mass selection of a precursor (parent) ion in the fi rst stage, (2) energy deposition into this selected precursor ion to induce fragmentation via cleavage of covalent chemical bonds, and (3) mass spectrometric detection of the resulting product (fragment) ions. This fundamental operating principle can be achieved in two conceptually different implementations, as illustrated in Figure 3.1: tandem in space MS/MS utilizing at least two consecutive mass analyzers or tandem in time MS/MS involving a series of mass analyses in a single mass analyzer. Several techniques, including traditional enzymatic sequencing methods, are available for structural characterization of nucleic acids. For example, nuclear magnetic resonance spectroscopy CONTENTS