Refereed journal article or data article (A1)
Hot electron-induced electrochemiluminescence of calcein and calcein-Tb(III) complex at disposable oxide-covered aluminum and polyvinyl butyral-carbon black/metal composite electrodes in aqueous solutions
List of Authors: Kalle Salminen, Päivi Grönroos, Harri Härmä, Sakari Kulmala
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Publication year: 2018
Journal: Electrochimica Acta
Journal name in source: ELECTROCHIMICA ACTA
Journal acronym: ELECTROCHIM ACTA
Volume number: 266
Start page: 212
End page: 219
Number of pages: 8
ISSN: 0013-4686
DOI: http://dx.doi.org/10.1016/j.electacta.2018.02.016
Abstract
Hot electron-induced electrochemiluminescence (HECL) of calcein and calcein-Tb(III) complex was generated at oxide-covered aluminum electrode during cathodic pulse polarization. The excitation of calcein as a molecule or as a ligand is based on subsequent one-electron oxidation and reduction steps by oxidizing radicals and solvated electrons. During HECL excitation of calcein-Tb(III) solution a reaction product of the calcein is formed that also enables the photoexcitation of Tb(III) via the formed ligand derivative by ligand-sensitized mechanism. The determination of low concentrations of calcein with aluminum electrodes was complicated by a relatively strong background electroluminescence originating from the Al2O3-layer. Polyvinyl butyral-carbon black composite electrodes coated on brass were fabricated to solve this problem and a fifty-fold lower background emission was obtained for these novel composite electrodes in comparison to that of oxide-covered 99.9% pure aluminum electrodes. The obtained detection limits were 3.2.10(-10) M for calcein and 6.4.10(-9) M for calcein-Tb(III) at the present composite electrodes. These species could potentially be utilized as electrochemiluminescent labels in bioaffinity assays. (C) 2018 Elsevier Ltd. All rights reserved.
Hot electron-induced electrochemiluminescence (HECL) of calcein and calcein-Tb(III) complex was generated at oxide-covered aluminum electrode during cathodic pulse polarization. The excitation of calcein as a molecule or as a ligand is based on subsequent one-electron oxidation and reduction steps by oxidizing radicals and solvated electrons. During HECL excitation of calcein-Tb(III) solution a reaction product of the calcein is formed that also enables the photoexcitation of Tb(III) via the formed ligand derivative by ligand-sensitized mechanism. The determination of low concentrations of calcein with aluminum electrodes was complicated by a relatively strong background electroluminescence originating from the Al2O3-layer. Polyvinyl butyral-carbon black composite electrodes coated on brass were fabricated to solve this problem and a fifty-fold lower background emission was obtained for these novel composite electrodes in comparison to that of oxide-covered 99.9% pure aluminum electrodes. The obtained detection limits were 3.2.10(-10) M for calcein and 6.4.10(-9) M for calcein-Tb(III) at the present composite electrodes. These species could potentially be utilized as electrochemiluminescent labels in bioaffinity assays. (C) 2018 Elsevier Ltd. All rights reserved.