Three-dimensionally ordered macroporous gold structure as an efficient matrix for solid-state electrochemiluminescence of Ru(bpy)32+/TPA system with high sensitivity

Tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) is generally considered as the most valuable electrochemiluminescence agent. For better utilization of this agent, various immobilization methods in different matrixes have been developed. However, its application is still subject to low stability and low sensitivity. Herein, we report on the fabrication of a three dimensionally (3D) ordered macroporous gold film electrode as the matrix for efficient immobilization of Ru(bpy)(3)(2+) in zirconia-Nafion sol-gel film. The 3D macroporous gold film with good conductivity has a large active surface area and interconnected macroporous structure, which enhance loading of the electrochemiluminescence (ECL) agent and mass transport of the analytes. In addition, Ru(bpy)(3)(2+) immobilized on the macroporous gold electrodes is more electrochemically accessible than it is on flat gold electrodes. These effects enable us to obtain high sensitivity of the presented sensor. As a demonstration, tripropylamine (TPA) was used as the model compound. Excellent performance of the presented sensor can be achieved, for example, the ECL response of the sensor to TPA shows a wide linear range from 1.0 nM to 10.0 mu M with a detection limit down to 0.5 nM.