Highly efficient quenching of tris(2,2′-bipyridyl)ruthenium(ii) electrochemiluminescence by ozone using formaldehyde, methylglyoxal, and glyoxalate as co-reactants and its application to ozone sensing

Abstract

Most electrochemiluminescence (ECL) systems require high concentrations of quencher to totally quench ECL. In this study, we found that ozone can quench tris(2,2′-bipyridyl)ruthenium(II) ECL using formaldehyde, methylglyoxal, or glyoxalate as co-reactants at a glassy carbon electrode with remarkable efficiencies even when the concentration of ozone is merely 0.25% of that of the co-reactant. The strongest quenching is observed with the tris(2,2′-bipyridyl)ruthenium(II)/formaldehyde ECL system. The tris(2,2′-bipyridyl)ruthenium(II)/formaldehyde ECL intensities decrease linearly with the ozone concentration over the range of 0.025–25 μM (r = 0.9947) with a limit of detection of 8 nM. The method is more sensitive and faster than most methods. It shows high selectivity in the presence of other ROS or oxidants and some metal ions, such as H₂O₂, ClO⁻, Mg²⁺, Ni²⁺, etc. The method exhibits high recoveries for the detection of ozone in a ventilated photocopy room.