Electroactivity of superoxide anion in aqueous phosphate buffers analyzed with platinized microelectrodes

Pauline Lefrancois (1) , Fanny Girard-Sahun (2, 1) , Vasilica Badets (1, 3) , Franck Clement (4) , Stéphane Arbault (5)

1 UB - Université de Bordeaux
2 UPPA - Université de Pau et des Pays de l'Adour
3 UNISTRA - Université de Strasbourg
4 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
5 ISM - Institut des Sciences Moléculaires

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.

Keywords: superoxide; ultramicroelectrode; hydrogen peroxide; reactive oxygen species; cold atmospheric plasma

Domains: Analytical chemistry; Catalysis; Plasmas

Pauline Lefrancois, Fanny Girard-Sahun, Vasilica Badets, Franck Clement, Stéphane Arbault. Electroactivity of superoxide anion in aqueous phosphate buffers analyzed with platinized microelectrodes. Electroanalysis, 2020, ⟨10.1002/elan.202060456⟩. ⟨hal-03014128⟩