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

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- C 2 , 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.