Fast peroxymonocarbonate formation on aqueous aerosols

Abstract

Peroxymonocarbonate (HCO₄-) is a reactive oxygen species previously studied in chem. manufg. and water detoxification. However, its role in atm. chem. remains largely unexplored despite its high oxidative potential via oxygen-atom transfer reactions (E(HCO₄-/HCO₃-) = 1.8V) and the abundance of CO₂, H₂O and H₂O₂ in the atm. This work explores the formation of HCO₄- at the interface of an aq. H₂O₂ jet and an intersection stream of CO₂ gas in an online electrospray ionization mass spectrometry (o-ESI-MS) reacting for ~50 µs. The interfacial kinetics of HCO₄- formation is measured to be >10⁴ times faster than the bulk phase kinetics, possibly due to the incomplete hydrogen bonding network at the gas-liq. interface. Peroxymonocarbonate may play an important yet previously unexplored role in the oxidn. of atm. sulfides, (bi)sulfites and alkenes such as isoprene and pinene.