A nano-TiO2 supported AuAg alloy nanocluster functionalized electrode for sensitizing the electrochemiluminescent analysis

A nano-hybrid of nano-titania supported AuAg alloy nanocluster was synthesized. It was then modified onto the surface of indium tin oxide (ITO) coated glass to act as a working electrode for exciting the electrochemiluminescence (ECL) of luminol. The properties of the nano-hybrid and the functionalized electrode were characterized by X-ray diffraction spectroscopy (XRD), electrochemistry, spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Coupled with microemulsion as a carrying matrix with the flow-injection analysis (FIA) mode, the ECL emission of luminol is greatly intensified on this functionalized electrode. Till to pH 6.0, needless any added co-reactant, the synergic sensitizing effect of nano-hybrid and microemulsion increased the ECL signal of luminol to a recordable level for the first time. The ECL response for H2O2 on this functionalized electrode gains a descended mass detection limit (LODM) for 1/230 than before. This research very significantly extended the area of ECL applications due to the extended practicable pH range which was suitable for environmental or biological targets etc. As an example, this intensified ECL was successfully applied to evaluate the gross antioxidant activity of some fruits with satisfactory results.