研究了在铟锡氧化物（ITO）电极上三羟甲基氨基甲烷（Tris）促进[Ru(bpy)3]2+（bpy = 2,2′-联吡啶）对次黄嘌呤（Hx）的电催化氧化作用. 结果表明，Tris的加入明显地增强了[Ru(bpy)3]2+对Hx的电催化氧化，扫描速度、溶液pH和Hx浓度对Hx电催化氧化均有明显的影响，Hx电催化氧化产物能与Tris发生后续的化学反应，[Ru(bpy)3]2+对Hx的催化氧化是基于后续化学反应增强均相电催化反应（EC′C）的机理. 在10 mmol/L Tris/50 mmol/L NaCl (pH 7.2)缓冲溶液中，Hx的电催化氧化电流在0.10 ~0.15 mmol/L区间随Hx浓度线性地增大，相关系数为0.991，检测限为0.12 μmol/L (S/N = 3).
The electrocatalytic oxidation of hypoxanthine (Hx) by [Ru(bpy)3]2+ (bpy = 2,2′-bipypyridine) on an indium-tin oxide (ITO) electrode upon incorporation of tris(hydroxymethyl)aminomethane (Tris) has been investigated. The addition of Tris is found to obviously promote the electrocatalytic oxidation of Hx by [Ru(bpy)3]2+ on the ITO electrode. The electrocatalytic oxidation of Hx is influenced by scan rate, pH value and Hx concentration. The XPS analysis reveals the presence of following chemical reactions between the oxidized products of Hx and Tris. Taken together, the electrochemical oxidation of Hx in Tris-containing buffer solutions is attributed to an EC′C mechanism, which is a special type of following chemical reaction coupled to the homogeneous electrocatalysis. In buffer solutions containing 10 mmol?L?1 Tris/50 mmol?L?1 NaCl (pH 7.2), the electrocatalytic currents increase linearly with increasing Hx concentration in the range from 0.1 μmol?L?1 to 0.15 mmol?L?1. The correlation coefficient is 0.991 and the detection limit of Hx is 0.12 μmol?L?1 (S/N = 3).