Superoxide radical (O-2(center dot-)) was both electrochemically generated and detected at room temperature. In situ ESR spectroelectrochemistry with spin trapping was used for the radical detection. That is, the O-2(center dot-) radical was obtained in a DMSO solution under cyclic voltammetry conditions as soon as the potential of the dioxygen electroreduction was reached. This radical reacted then with a 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin-trap reagent present in solution to form the DMPO-(OOH)-O-center dot adduct. The hyperfine coupling constants determined for the adduct were a(N) = 1.285 mT, a(H)(beta) = 1.042 mT and a(H)(gamma) = 0.142 mT in accord to those reported in literature. (C) 2007 Elsevier Ltd. All fights reserved.