pH-switched electrochemistry of pyrroloquinoline quinone at Au electrodes modified by functionalized monolayers

Autor:	Mazzi Lion-Dagan, Eugenii Katz, Itamar Willner
Rok vydání:	1996
Předmět:	Chemistry Stereochemistry General Chemical Engineering Electrochemical kinetics Buffer solution Photochemistry Electrochemistry Electrocatalyst Redox Amperometry Analytical Chemistry chemistry.chemical_compound Pyrroloquinoline quinone Monolayer
Zdroj:	Journal of Electroanalytical Chemistry. 408:107-112
ISSN:	1572-6657
Popis:	Gold electrodes were modified with thiolate monolayers that included dissociative groups of different p K a values: cystamine, 4-aminothiophenol and 4-pyridyl disulfide. The electrochemistry of the redox probe pyrroloquinoline quinone (PQQ) was examined in a broad pH region using the different monolayer-modified electrodes. The redox probe PQQ reveals reversible electrochemical properties only in the presence of positively-charged monolayer-modified electrodes, owing to its electrostatic attraction to the monolayer/vbelectrode interface. For the different monolayer-modified electrodes exhibiting different p K a values, the transition from a reversible to an irreversible electrochemical process for PQQ was observed at different pH values. The electrochemical response of the modified-electrode system can be reversibly switched between ON and OFF states by controlling the pH of the assemblies in a narrow range. The transduced amperometric signals at the different pH environments were amplified by the PQQ-electrocatalyzed oxidation of NADPH in the presence of Ca 2+ . The electrode systems represent novel examples of pH-controlled electrochemical ON-OFF systems.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::442eb1f0e3802ed7b472dcb3c9e1bcf6 https://doi.org/10.1016/0022-0728(96)04525-1 Zobrazit plný text záznamu Full Text from ScienceDirect