Investigation on the electrochemiluminescent behaviors of oxypurinol in alkaline Ru(bpy)32+ solution using a flow injection analytical system

Electrochemiluminescent (ECL) behaviors of oxypurinol in alkaline tris(2,2-bipyridine)ruthenium(II) (Ru(bpy)32+) solution were studied in a flow injection electrochemiluminescent system (FI-ECL) in this paper. It was found that the ECL response of oxypurinol was significantly pH-dependent. It inhibited the ECL of Ru(bpy)32+ at ⩽pH 10.0, whereas exhibited enhanced ECL response at pH ⩾ 11.0. Additionally, other experimental conditions such as the applied potential of working electrode, the flow rate of carrier solution, and the concentration of Ru(bpy)32+ were all observed to affect the ECL response of oxypurinol. Under the optimum conditions, the logarithm of enhanced ECL intensity, ΔI, was found linearly proportional to the logarithm of oxypurinol concentration in the range of 1.0 × 10−7–1.0 × 10−4 mol L−1, and the detection limit (S/N = 3) was 3.0 × 10−9 mol L−1. The mechanism of inhibited and enhanced Ru(bpy)32+ ECL by oxypurinol was studied, and a new and sensitive flow injection analysis (FIA) method basing on the enhanced ECL was proposed for detection of oxypurinol.