The doubly‐charged ion mass spectra of hydrocarbons

Abstract

Abstract The doubly‐charged ion mass spectra of some hydrocarbons, including a variety of structural types, have been obtained by a new technique in which doubly‐charged ions are charge exchanged with neutral molecules and so separated from singly‐charged ions. The spectra show strong similarities, independent of hydrocarbon structure; characteristic ions include [C m H 2 ] ++ ( m = 2 to 5), [C n H 6 ] ++ ( n > 6), [C 10 H 8 ] ++ , [C 12 H 8 ] ++ , [C 11 H 10 ] ++ , [C 7 H 7 ] ++ ·, [C 9 H 7 ] ++ · and [C 13 H 11 ] ++ ·. The fragmentation pattern of 2‐phenylnaphthalene has been reconstructed, based on observed reactions of metastable doubly‐charged ions to give fragment doubly‐charged ions. In addition, we examined metastable ion fragmentations leading to two singly‐charged ions for some of the characteristic ions, using several compounds. The value of doubly‐charged ion mass spectra of hydrocarbons appears to lie in the information they provide on ion structures; this information was sufficient to permit the proposal of structures for the major ions encountered in this study.