A redox-mediator pathway for enhanced multi-colour electrochemiluminescence in aqueous solution

Abstract

The classic and most widely used co-reactant electrochemiluminescence (ECL) reaction of tris(2,2′-bipyridine)ruthenium(II) ([Ru(bpy)₃]²⁺) and tri-n-propylamine is enhanced by an order of magnitude by fac-[Ir(sppy)₃]³⁻ (where sppy = 5′-sulfo-2-phenylpyridinato-C²,N), through a novel ‘redox mediator’ pathway. Moreover, the concomitant green emission of [Ir(sppy)₃]³⁻* enables internal standardisation of the co-reactant ECL of [Ru(bpy)₃]²⁺. This can be applied using a digital camera as the photodetector by exploiting the ratio of R and B values of the RGB colour data, providing superior sensitivity and precision for the development of low-cost, portable ECL-based analytical devices.