A MWCNTs-Pt nanohybrids-based highly sensitive electrochemiluminescence sensor for flavonoids assay

Electrochemiluminescent (ECL) assay has gradually drawn increasing interest to be considered as one of the potential strategies to be applicable in a wide range of medicine target determination. In this protocol, a facile and ultrasensitive ECL sensor platform was developed aiming at rapidly quantitative detection of polyphenolic flavonoids based on multiwall carbon nanotubes (MWCNTs)/platinum nanoparticles (PtNPs) nanohybrids/nafion/Ru(bpy)₃²⁺ modified glassy carbon electrode (GCE) in Ru(bpy)₃²⁺/tri-n-propylamine (TPA) co-reaction system. Attributed to the synergistic ECL signal amplification of both PtNPs and MWCNTs facilitating the electron transfer, this proposed sensor could sensitively analyze the flavonoids through an annihilation ECL emission mechanism since the less generated amount of excitation state Ru(Ⅱ)* on account of the principle that flavones are prone to donate electrons and scavenge free radicals to further show a competitive relationship with Ru(Ⅲ) on the reaction with TPA*. The influences of pH, Ru(bpy)₃²⁺ absorption time and TPA co-reactant concentration were investigated and the sensor exhibited a linear response to flavonoids when the concentration ranges from 6.50×10^-11 to 1.00×10^-7M with a detection limit (LOD) of 2.17×10^-11M (S/N=3) upon the optimized conditions. Furthermore, high sensitivity, excellent stability and reproducibility were verified to declare the promise for being applicable to analyze the flavones content in real flavones medicine samples and ginkgo leaves extracts with satisfactory results.