Recognition of glutathione based on its electrocatalytic oxidation on the bare fluorine doped tin oxide electrode

•Bare fluorine doped tin oxide (FTO) can catalyze glutathione (GSH) oxidation.•Electrocatalytic oxidation of GSH at FTO electrode is very sensitive to pH.•Lower oxidation peak potential of GSH at the FTO electrode•A novel strategy for recognition of GSH from the 20 α-amino acids and other species•Detection limit for recognition of GSH is 5 nM at pH 4.4.

We revealed that the bare fluorine doped tin oxide (FTO) exhibited the electrocatalytic ability towards the oxidation of glutathione (GSH) in a narrow pH region, which was examined using linear sweep voltammetry (LSV). LSV indicated that an oxidation peak of GSH at the FTO electrode occurs at 0.27 V (vs. SCE) that is 0.77 V negative of that at the bare Pt electrode, and GSH cannot be oxidized at the glassy carbon (GC) electrode in a potential region − 0.40 to 1.20 V, at pH 4.4. On the basis of the electrocatalytic oxidation of GSH in a narrow pH region 4.0-5.5 and its lower oxidation peak potential, the bare FTO electrode can be used as a probe to recognize GSH from the 20 α-amino acids present in proteins, cystine, homocysteine, cysteamine, thiobenzoic acid, ascorbic acid, catechol, and dopamine. Its detection limit for the recognition of GSH is 5 nM.

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