Electrochemcial detection of superoxide radical anion

Abstract

Superoxide radical anion (O2-) is a short-lived, extremely reactive species formed upon one-electron reduction of ground state triplet oxygen. O2-, in the aqueous medium abstracts a proton to produce H02 which disproportionates to give H₂O₂ and hydroxyl radicals (OU). All these species are good oxidants that can attack organic pollutants in the aquatic systems. The formation and the role of O2- in the biological systems are also of great concern in terms of the cytotoxicity of O2- towards many cellular constituents. O2- also involves in the defense against viral and bacterial attacks. Therefore, a development of a quantitative method to determine O²-in solution is very important. In this respect we have tested several quinone type compounds as mediators for the design and development of an electrochemical method for the detection of O²"-. Listed below are some of the materials we have investigated in acetonitrile.

(Table)

As can be seen from the above table, 1,2,3-triketohydrindene hydrate is a promising O2- quencher similar to that of l,4-benzoquinone. Detailed mechanistic studies reveal that the compound reacts immediately with O2- once formed, and therefore, acts as a mediator for the detection of O2-