A novel electrochemical sensing system for inosine and its application for inosine determination in pharmaceuticals and human serum

The voltammetric behaviors of inosine at La(OH)3 nanowires (LNW) modified carbon paste electrode (LNW/CPE) in the presence of Cu(II) ion and K2S2O8 were investigated. The oxidation peak at 0.20 V was attributed to inosine oxidation in the formed inosine–Cu(II) complex, while the reduction peak at −0.20 V was attributed to Cu(II) ion reduction in the complex. The electrochemical oxidation potential of inosine was reduced, and the analytical sensitivity and selectivity was improved. A novel sensing system for monitoring inosine was proposed. The oxidation peak current at 0.20 V was rectilinear with inosine concentration in the range of 4.0 × 10−9–2.0 × 10−8 mol L−1, with a detection limit of 8.3 × 10−10 mol L−1. The proposed system was applied to inosine determination in both pharmaceutical preparations and human serum.