Electroactivity of superoxide anion in aqueous phosphate buffers analyzed with platinized microelectrodes
Résumé
The reactivity of platinized ultramicroelectrodes (Pt-black UMEs) towards superoxide anion O 2 *À , an unstable Reactive Oxygen Species (ROS), and its relatives, H 2 O 2 and O 2 , was studied. Voltammetric studies in PBS demonstrate that Pt-black UMEs provide: i) a wellresolved reversible redox signature for O 2 *À detected in both alkaline and physiological buffers (pH 12 and 7.4); ii) irreversible oxidation and reduction waves for H 2 O 2 at pH 7.4. The oxygen reduction reaction (ORR) at Pt-black surfaces solely yields H 2 O 2 (2 electrons/2 H +) at physiological pH. Consequently, Pt-black UMEs allow to sense different ROS including superoxide anion for future biomedical or physico-chemical investigations.
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