Recent Developments in Gas-Phase Ion/Ion Reactions for Analytical Mass Spectrometry.

Abstract

While the study of reactions between oppositely-charged ions has a long history, particularly within the context of plasmas and interstellar chemistry, the exploitation of such reactions for analytical applications was made possible with the advent of electrospray ionization (ESI). , ESI provides a means for generating abundant multiply-charged ions from a wide variety of molecular classes. It was then possible to use ESI to generate multiply-charged analyte or reagent ions for reactions with ions of opposite polarities without resulting in complete neutralization. The first description of ion/ion reaction studies using ESI was given by Loo et al. using a Y-tube reactor leading to the inlet of an atmosphere/vacuum interface coupled with a quadrupole mass filter. , This was an early example of ion/ion chemistry being effected prior to sampling ions into a mass spectrometer. The first implementation of ion/ion reactions within the context of a MSn experiment was demonstrated at Oak Ridge National Lab. , Thi...