Impact of aminated carbon quantum dots as a novel co-reactant for Ru(bpy)₃²⁺: resolving specific...

Development of novel nanomaterial-based co-reactant is highly desired for enhancing ECL intensity and widespread analytical applications. Herein, we report the distinct role of amine-functionalized carbon quantum dots (f-CQDs) as a co-reactant, for the first time, augmenting the ECL property of Ru(bpy)₃²⁺ and demonstrating for biopharmaceutical (butein) detection. Unlike conventional co-reactants like tripropylamine (TPrA), 2-(dibutylamino)ethanol (DBAE), and pristine CQDs, the f-CQDs as a co-reactant yield superior ECL of Ru(bpy)₃²⁺. More importantly, the ECL intensity is independent of types of noble metals, metal oxide surfaces, and dissolved oxygen. Notably, the ECL intensity of Ru(bpy)₃²⁺-f-CQDs is linearly quenched with an increased concentration of butein, whereas no changes were observed with conventional co-reactants. ECL functionality of Ru(bpy)₃²⁺-f-CQDs has no interference with other similar phytochemicals and antioxidants. Enhanced selectivity is observed due to the formation of polyaminoquinone-like structures, which is confirmed by in situ spectroelectrochemical (UV-vis) and FT-IR studies. The present result envisaged that f-CQDs could be an alternative co-reactant for TPrA/DBAE, raising the ECL of Ru(bpy)₃²⁺ suitable for analytical studies. Graphical abstract.