Hot Electron-Induced Electrogenerated Chemiluminescence of Ru(bpy)₃²⁺ Chelate at Oxide-Covered Aluminum Electrodes

Abstract

Ruthenium(II) tris-(2,2‘-bipyridine) chelate exhibits strong electrogenerated chemiluminescence during cathodic pulse polarization of oxide-covered aluminum electrodes in aqueous solutions. The present method is based on a tunnel emission of hot electrons into an aqueous electrolyte solution. The method allows the detection of ruthenium(II) tris-(2,2‘-bipyridine) and its derivatives below nanomolar concentration levels and yields linear log−log calibration plots spanning several orders of magnitude of concentration. This method allows simultaneous excitation of derivatives of ruthenium(II) tris-(2,2‘-bipyridine) and Tb(III)-chelates. The former label compounds have a luminescence lifetime of the order of microseconds, while the latter compounds generally have a luminescence lifetime of around 2 ms. Thus, the combined use of these labels easily provides the basis for two-parameter bioaffinity assays by either using wavelength or time discrimination or their combination.

Chemiluminescent investigation of tris(2,2'-bipyridyl)ruthenium(II) immobilized on a cationic ion-exchange resin and its application to analysis

“…Potential for the ground-and excited-state couples involving Ru(bpy) 3 2+ have been noted in previous papers [30,31,32,33]. The redox potential data summarized by Bock [34] are listed below.…”

Heterogeneous oligonucleotide-hybridization assay based on hot electron-induced electrochemiluminescence of a rhodamine label at oxide-coated aluminum and silicon electrodes

“…Many common photoluminescent and chemiluminescent luminophores have been detected this way, examples including luminol and its derivatives [10,11], Ru(bpy) 3 2+ [12,13], fluorescein and eosin [14], SYBR (R) Green I [15], coumarine dyes [16], Rhodamine B [17] and terbium chelates [18,19]. The most sensitive HECL luminophores so far are terbium labels, which can be detected down to femtomolar concentration [18,19].…”

“…A distinct advantage of HECL over anodic ECL is that various luminophores with different optical and redox properties can be simultaneously excited [14,20]. HECL has been previously used for biorecognition detection in immunoassays [12,[21][22][23]. Capturing antibodies were physically adsorbed on oxide-coated aluminum [12,21,22] and silicon [23] electrodes and the biorecognition reaction was detected using target antibodies labeled with HECL labels.…”

“…HECL has been previously used for biorecognition detection in immunoassays [12,[21][22][23]. Capturing antibodies were physically adsorbed on oxide-coated aluminum [12,21,22] and silicon [23] electrodes and the biorecognition reaction was detected using target antibodies labeled with HECL labels. Immunoassays and nucleic acid probing techniques share many similarities, as they are both based on a unique biorecognition process, however, there are some fundamental differences due to the fact that antibodies are relatively large molecules (MW ≈ 160 kDa) while DNA-assays utilize short oligonucleotides (MW ≈ 5-10 kDa).…”

Cathodic electrochemiluminescence of lucigenin at disposable oxide-coated aluminum electrodes

“…In practice, cathodic reductions may be produced simultaneously by heterogeneously transferred electrons from the bottom of the conduction band of the insulating film, via the surface states of the insulating film and by presolvated hot and hydrated electrons [25]. Meanwhile, strongly oxidizing species such as sulfate and hydroxyl radicals can be cathodically generated from purposely-added coreactants or form dissolved oxygen [22,23,25,33,34]. In addition, F + -centers existing in oxide film of C/I/E electrodes may act as oxidants [2,23,33].…”