| Abstract: | A corona discharge atmospheric pressure ionization source generates the reagent ions, OH? and O? ions in addition to better known O2? ions, when ambient air is used as the carrier. All three ions are gas-phase bases that could form negative ions from organics via proton abstraction. Ionization of simple aromatic hydrocarbons by O2? is thermodynamically not feasible. Simple aromatic hydrocarbons are ionized only by O? and/or OH? to form M ? H]? ions. However, M ? H]? ions do not appear in the mass spectrum as they undergo stabilization via clustering with predominantly oxygen atoms. |
