‘Cathodic’ electrochemiluminescence of [Ru(bpy)3]2+ and tri-n-propylamine confirmed as emission at the counter electrode

A new approach to examine electrochemiluminescence (ECL), in which the potentials at both the working and counter electrodes are measured and the emitted light is detected by a photomultiplier tube, camera and then a charge-coupled device (CCD) spectrometer, provides unequivocal evidence that the purported cathodic ECL of [Ru(bpy)3]2+ and tri-n-propylamine actually arises from anodic reactions at the counter electrode.