Investigating the viability of electrodeposited vanadium pentoxide as a suitable electrode material for in vivo amperometric hydrogen sulfide detection

A vanadium pentoxide (V₂O₅) film was electrodeposited onto the end of a PtIr wire (d = 125 μm) via potential cycling in order to preliminarily assess its viability as a prospective material for in vivo H ₂S monitoring. The deposited oxide film exhibited catalytic activity towards the oxidation of H₂S in a physiologically relevant pH buffer solution, which resulted in a large increase in peak current compared to that exhibited by the bare PtIr surface. The modified electrode exhibited a linear response over a total sulfide concentration range of 0.5-15 μM. The catalytic activity of the V₂O₅-modified wire towards the oxidation of upper physiological levels of NO and CO, two gaseous interferences found in vivo, was investigated using amperometry. While the electrode demonstrated some activity towards NO, it exhibited significant activity towards CO in the potential region of interest. However, the response towards NO and CO was much slower than the response towards H₂S and the linear range remained unchanged despite the presence of the interfering gases.