- Electrochemiluminescence
Electrochemiluminescence or electrogenerated chemiluminescence (ECL) is a kind of
luminescence produced during electrochemical reactions in solutions. ECL excitation is caused by energetic electron transfer (redox) reactions of electrogenerated species. Suchluminescence excitation is is a form ofchemiluminescence where one/all reactants are produced electrochemically on the electrodes. [Electrogenerated Chemiluminescence, Edited by Allen J. Bard, Marcel Dekker, Inc., 2004]
ECL is usually observed during application of potential (several Volts) to electrodes of electrochemical cell that contains solution of luminescent species (polycyclic aromatic hydrocarbons, metal complexes) in aprotic organic solvent (ECL composition).Application
ECL proved to be very useful in analytical applications as a highly sensitive and selective method. It combines analytical advantages of chemiluminescent analysis (absence of background optical signal) with ease of reaction control by applying electrode potential. Enhanced selectivity of ECL analysis is reached by variation of electrode potential thus controlling species that are oxidized/reduced at the electrode and take part in ECL reaction [Fahnrich K.A., Pravda M., Guilbault G.G., Recent Applications of Electrogenerated Chemiluminescence in Chemical Analysis, Talanta, 54 (4), 531-559, 2001] (see
electrochemical analysis ).It generally uses Ruthenium complexes, esp [tris(bipyridine)ruthenium(II) chloride| [Ru (Bpy)3] 2+] (which releases a photon at ~620 nm) regenerating with TPA (
Tripropylamine ) in liquid phase or liquid-solid interface. It can be used as monolayer immobilized on an electrode surface (made eg ofnafion , or special thin films made by Langmuir-Blogett technique or self-assembly technique) or as a coreactant or more commonly as a tag and used inHPLC , Ru tagged antibody based immunoassays, Ru Tagged DNA probes forPCR etc,NADH orH2O2 generation based biosensors, oxalate and organic amine detection and many other applications and can be detected from picomolar sensitivity to dynamic range of more than six orders of magnitude. Photon detection is done withPMT or siliconephotodiode or gold coatedfiber-optic sensors. ECL is heavily used commercially for many clinical lab applications. [Tris (2, 2′-bipyridyl) ruthenium (II) electrogenerated chemiluminescence in analytical science; Mikrochimica acta [0026-3672] Lee yr:1997 vol:127 iss:1 pg:19 ]ee also
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Chemiluminescence References
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