Selected ion flow tube (SIFT) studies of the reactions of H3O+, NO+ and O-2(+center dot) with six volatile phytogenic esters
Abstract
The selected ion flow tube (SIFT) was used to study the reactions of the three SIFT-MS precursor ions H3O+, NO+ and O-2(+center dot) with six phytogenic esters: hexyl acetate, phenethyl acetate, benzyl acetate, methyl salicylate, methyl benzoate and benzyl benzoate. These compounds are emitted into the atmosphere by various species of plants and play a role in communication between individual plants and also amongst different species.
Thus, it is necessary to know the rate constants and branching ratios of the different ion products of these reactions for identification and quantification by SIFT-MS. The results of this study show that the reactions of H3O+ with the esters proceed via proton transfer, which is non-dissociative for methyl salicylate, entirely dissociative for benzyl benzoate and partly dissociative for the remaining four esters.
All protonated esters readily associate with water molecules with the notable exception of methyl salicylate.