biostudies-literatureBraxton ERoyal SocietyEngineering and Physical Sciences Research Council21-31https://www.ebi.ac.uk/biostudies/studies/S-EPMC9936800biostudies-literatureUnknown3(1)For the detection of electrochemically produced hydroxyl radicals (HO^·) from the oxidation of water on a boron-doped diamond (BDD) electrode, electron paramagnetic resonance spectroscopy (EPR) in combination with spin trap labels is a popular technique. Here, we show that quantification of the concentration of HO^· from water oxidation via spin trap electrochemical (EC)-EPR is problematic. This is primarily due to the spin trap oxidizing at potentials less positive than water, resulting in the same spin trap-OH^· adduct as formed from the solution reaction of OH^· with the spin trap. We illustrate this through consideration of 5,5-dimethyl-1-pyrroline <i>N</i>-oxide (DMPO) as a spin trap for OH^·. DMPO oxidation on a BDD electrode in an acACS measurement science auElectron Paramagnetic Resonance for the Detection of Electrochemically Generated Hydroxyl Radicals: Issues Associated with Electrochemical Oxidation of the Spin Trap.PMC9936800EP/V056778/1EP/L015307/1INF/PHD/180016EP/L015315/1Fox DJBraxton ENewton MEBreeze BGTully JJLevey KJMacpherson JVfalseElectron Paramagnetic Resonance for the Detection of Electrochemically Generated Hydroxyl Radicals: Issues Associated with Electrochemical Oxidation of the Spin Trap.For the detection of electrochemically produced hydroxyl radicals (HO^·) from the oxidation of water on a boron-doped diamond (BDD) electrode, electron paramagnetic resonance spectroscopy (EPR) in combination with spin trap labels is a popular technique. Here, we show that quantification of the concentration of HO^· from water oxidation via spin trap electrochemical (EC)-EPR is problematic. This is primarily due to the spin trap oxidizing at potentials less positive than water, resulting in the same spin trap-OH^· adduct as formed from the solution reaction of OH^· with the spin trap. We illustrate this through consideration of 5,5-dimethyl-1-pyrroline <i>N</i>-oxide (DMPO) as a spin trap for OH^·. DMPO oxidation on a BDD electrode in an ac2023-01-01T00:00:00Z2023 Feb2025-04-26T14:53:50.384Z2025-04-06T14:46:34.357ZS-EPMC99368003681700610.1021/acsmeasuresciau.2c00049