TiO₂/Ag-based photodeposited catalyst boosted electrochemiluminescence of ninhydrin-hydrogen peroxide system for...

Photodeposited TiO₂/Ag nanocomposites were generally used to be a friendly catalyst for degrading organic contaminant in environmental field. However, electrochemiluminescence (ECL) sensing analysis based on photocatalysts remains a significant challenge. Herein, polyvinylimide (PEI)-TiO₂/Ag nanocomposites (PEI-TiO₂/AgNCPs) film with reduced graphene oxide(r-GO) was constructed as a sensing interface for copper(II) ECL detection. TiO₂/Ag nanocomposites was prepared by reversed phase microemulsion method and photodeposition technique. Moreover, it was discovered that a small amount of Cu²⁺ could obviously boost the ECL signal of ninhydrin-hydrogen peroxide system. Signal amplification was achieved by using the synergistic effect between r-GO and TiO₂/Ag nanocomposites, and the efficiently concentrated effect of PEI to Cu²⁺. Furthermore, the investigation showed that ECL mechanism of ninhydrin-hydrogen peroxide system was attributed to the generated hydroxyl radical and superoxide anion during the several type of reactions. Thus for the first time, an ultrasensitive ECL approach for detecting Cu²⁺ could be performed using ninhydrin as an ECL signal probe and hydrogen peroxide as a co-reaction reagent. Under the suitable circumstances, the proposed method showed an excellent linear relationship in the concentration range of Cu²⁺ from 1.0 fM to 5.0 nM. Detection limit was estimated to be as low as 0.26 fM. The sensing interface expanded the application of photodeposited TiO₂/Ag nanocomposites in ultrasensitive ECL detection. It has potential applications in other components and biological analysis.