Acetone chemical ionization mass spectrometry

Abstract

Chemical ionization mass spectrometry (CIMS) is often used for the characterization of thermally stable and electron impact-labile compounds, and acetone is one of the CI reagent gases used not only to characterize the analytes but also to differentiate regio- and stereoisomers. The nature of the reagent ions, the factors affecting the reagent plasma, and the type of ion-molecule reactions with the substrate molecules under acetone/CI are briefly discussed in this article. The ion-molecule reactions between the reagent ions and a wide variety of organic compounds are reviewed. The mechanisms involved in the formation of characteristic ions studied by using acetone-d₆ as a reagent and also by collision-induced dissociation of the respective adduct ions have been discussed. The site of acetylation in most of the substrates by the reagent ions of acetone has been found to depend on the nature and position of the substituents present in the substrate, and in some cases the acetylation reaction is controlled by the steric factors.