ABSTRACT
CO3 -⢠and O2 -⢠are known to be strong oxidizing reagents in biological systems. CO3 -⢠in particular can cause serious damage to DNA and proteins by H⢠abstraction reactions. However, H⢠abstraction of CO3 -⢠in the gas phase has not yet been reported. In this work we report on gas-phase ion/molecule reactions of CO3 -⢠and O2 -⢠with various molecules. CO3 -⢠was generated by the corona discharge of an O2 reagent gas using a cylindrical tube ion source. O2 -⢠was generated by the application of a 15 kHz high frequency voltage to a sharp needle in ambient air at the threshold voltage for the appearance of an ion signal. In the reactions of CO3 -â¢, a decrease in signal intensities of CO3 -⢠accompanied by the simultaneous increase of that of HCO3 - was observed when organic compounds with H-C bond energies lower than â¼100 kcal mol-1 such as n-hexane, cyclohexane, methanol, ethanol, 1-propanol, 2-propanol, and toluene were introduced into the ion source. This clearly indicates the occurrence of H⢠abstraction. O2 -⢠abstracts H+ from acid molecules such as formic, acetic, trifluoroacetic, nitric and amino acids. Gas-phase CO3 -⢠may play a role as a strong oxidizing reagent as it does in the condensed phase. The major discharge product CO3 -⢠in addition to O2 -â¢, O3, and NO x ⢠that are formed in ambient air may cause damage to biological systems.