CATHODIC ELECTROGENERATED CHEMILUMINESCENCE OF LUMINOL AT DISPOSABLE OXIDE-COVERED ALUMINUM ELECTRODES

Luminol exhibits strong electrogenerated chemiluminescence during cath odic pulse polarization of oxide-covered aluminum electrodes in aqueou s solution, This electrogenerated chemiluminescence can be enhanced by the presence of dissolved oxygen or by the addition of other coreacta nts such as hydrogen peroxide, peroxydisulfate, or peroxydiphosphate i ons, However, luminol detection is most sensitive in the presence of a zide ions, which not only enhance the electrogenerated chemiluminescen ce intensity but also decrease the intrinsic electroluminescence of th e thin aluminum oxide film on the electrodes mainly producing the blan k emission, ?he present method is based on tunnel emission of hot elec trons into an aqueous electrolyte solution and allows the detection of luminol, isoluminol, and its derivatives below nanomolar concentratio n levels, The linear logarithmic calibration range covers several orde rs of magnitude of concentration of luminol or N-(6-aminohexyl)-N-ethy lisoluminol. Therefore, the above-mentioned labeling substances can be used as one of several available alternatives of simultaneous markers in multiparameter bioaffinity assays at disposable oxide-covered alum inum electrodes, The main advantage of the present electrochemilumines cence generation method is that luminescent compounds having very diff erent photophysics and chemistry can be simultaneously excited, thus p roviding good possibilities for internal standardization and multipara meter bioaffinity assays.