Fabrication of CdS/Ru(bpy)₃²⁺electrochemiluminescence sensor for detection of catechol

A self-reinforced CdS/Ru(bpy)32+ electrochemiluminescence (ECL) sensor was constructed based on the sensitization of cadmium sulfide quantum dots (CdS QDs) to the ECL signal of tris(2,2'-bipyridyl)ruthenium(Ⅱ) (Ru(bpy)32+). CdS QDs were firstcoated dropwise on the electrode surface, and then a tris(2,2'-bipyridyl)ruthenium(Ⅱ) complex with multi-walled carbon nanotubes and gold nanoparticles (MWCNTs-Au NPs-Ru(bpy)32+)was introduced. The sensor has the characteristics of self enhancement since it contains both ECL material Ru(bpy)32+ and coreactant CDs QDs. The presence of MWCNTs and Au NPs can further amplify the sensor signal. The energy transfer between the electrode oxidation products of catechol and Ru (bpy)32+ led to the quenching of the ECL signal, realizing the sensitive detection of catechol with a linear response range from 5.0×10-9 to 1.0×10-5 mol·L-1 and a detection limit of 1.5×10-9 mol·L-1. The sensor showed good reproducibility and stability and was used to detect catechol in river water with satisfactory result