Analytical applications of electrochemiluminescence

Electro chemiluminescence is a form of chemiluminescence in which the light emitting reaction is preceded by an electrochemical reaction. The ECL reaction of an acridan ester is described as an example. With this kind of reaction of the advantages of CL are retained, but the electrochemical step allows the time and position of the light emitting reaction to be controlled. By controlling the time of the reaction light emission can be delayed until levels such as immune or enzyme catalyzed reactions have taken place, and by controlling the position light emission can be confirmed to a region that is precisely located with respect to the detector, improving sensitivity by increasing the ratio of signal to noise. The advantages will be highlighted by describing an enzyme ECL immunoassay for small molecules such as dinitrophenol, in which superparamagnetic bead technology is used to concentrate enzyme labeled antibodies on the surface of an electrode, in close proximity to the detector. Finally the future of research in this are will be examined by describing how bipolar electrodes can be used to free ECL from the constraints imposed on it by conventional 2D electrodes.