Chemical ionization of substituted naphthalenes using tetrahydrofuran as a reagent in gas chromatography with ion trap mass spectrometry.

The ion/molecule reactions of nine monosubstituted naphthalene compounds in chemical ionization mass spectrometry (CI-MS) were studied using tetrahydrofuran (THF) as CI reagent. Proton affinity factors, substituent effects and the preferred site of adduct ion attachment were examined. Good correlation was observed between proton affinity and the formation of [M](+*) and [M+H](+) ions. The influence of substituents on protonation and site-specific adduct [M+13](+) and [M+41](+) ion formation is also observed, with the cyano substituent showing the most stable [M+41](+) ion. Collision-activated dissociation experiments were used to characterize the variety of adducts formed under CI conditions, and provided insight into product ion structures and mechanisms of dissociation and condensation during CI-MS/MS. Copyright 2003 John Wiley & Sons, Ltd.