Electrochemiluminescence: Ruthenium Complexes

Electrochemiluminescence (ECL) is the generation of emitting excited Principle and states from electron transfer reactions of species that are generated electro-applications chemically at the surface of an electrode on application of applied potentials (Faulkner and Bard, 1977). These reactions have been the subject of theoretical study for a number of years and have largely centered on the use of very clean organic solvents requiring, in many cases, redistillation, recrystallization, deoxygenation, extensive drying of the reagents, and repeated polishing of the electrode surfaces used in the study (Faulkner and Bard, 1977; Abruna, 1985). Prior studies in aqueous solutions have been based on the use of organic acids at pHs from 3 to 6; however, the desired pH for detection of most biomolecules ist between 6 and 8 (Leland and Powell, 1990). Of the ECL species which have been studied, most efforts to date have been directed at Ru(bpy)3 2+ (bpy ist 2,2’-bipyridine) due to its electrochemical properties and quantum yield, and this is the ECL label we have made use to develop our assays.