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Double-layer capacitance of pH-sensitive self-assembled thiol layers on gold determined by electrical impedance spectroscopy in a microfluidic channel

2017; Wiley; Volume: 214; Issue: 9 Linguagem: Inglês

10.1002/pssa.201600921

1862-6319

Anne Kleppisius, Alfred Kick, Michael Mertig,

Electrochemical sensors and biosensors

physica status solidi (a)Volume 214, Issue 9 1600921 Original Paper Double-layer capacitance of pH-sensitive self-assembled thiol layers on gold determined by electrical impedance spectroscopy in a microfluidic channel Anne Kleppisius, Anne Kleppisius Kurt-Schwabe-Institut für Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Straße 4, 04736 Waldheim, GermanySearch for more papers by this authorAlfred Kick, Alfred Kick Kurt-Schwabe-Institut für Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Straße 4, 04736 Waldheim, GermanySearch for more papers by this authorMichael Mertig, Corresponding Author Michael Mertig mertig@ksi-meinsberg.de Kurt-Schwabe-Institut für Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Straße 4, 04736 Waldheim, Germany Professur für Physikalische Chemie, Mess- und Sensortechnik, Technische Universität Dresden, 01062 Dresden, Germany Corresponding author: e-mail mertig@ksi-meinsberg.de, Phone: +49 34327 608150, Fax: +49 34327 608 131Search for more papers by this author Anne Kleppisius, Anne Kleppisius Kurt-Schwabe-Institut für Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Straße 4, 04736 Waldheim, GermanySearch for more papers by this authorAlfred Kick, Alfred Kick Kurt-Schwabe-Institut für Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Straße 4, 04736 Waldheim, GermanySearch for more papers by this authorMichael Mertig, Corresponding Author Michael Mertig mertig@ksi-meinsberg.de Kurt-Schwabe-Institut für Mess- und Sensortechnik e. V. Meinsberg, Kurt-Schwabe-Straße 4, 04736 Waldheim, Germany Professur für Physikalische Chemie, Mess- und Sensortechnik, Technische Universität Dresden, 01062 Dresden, Germany Corresponding author: e-mail mertig@ksi-meinsberg.de, Phone: +49 34327 608150, Fax: +49 34327 608 131Search for more papers by this author First published: 09 March 2017 https://doi.org/10.1002/pssa.201600921Citations: 4Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract The determination of the double-layer capacitance of planar interdigitated gold electrodes in a microfluidic channel by electrical impedance spectroscopy is presented. A simple and miniaturized two-electrode setup is used to investigate electrodes coated with pH-sensitive self-assembled thiol layers of 4-mercaptopyridine (4-MP) or 4-mercaptobenzoic acid (4-MBA). The total sensing area is about 0.25 mm2. Surface modifications and pH have a pronounced influence on the double-layer capacitance of the electrodes. The interfacial capacitance rises significantly at pH < 3 on the 4-MP and at pH > 10 on the 4-MBA layer. This effect is related to surface protonation or deprotonation of the pyridine or carboxylic moieties, respectively. It is shown that this double-layer capacitance is widely independent from the electrolyte concentration. Such electrodes can be used as pH indicators in microfluidic channels, additionally allowing the determination of the electrolyte conductivity. This kind of sensor is supposed to be used in lab-on-a-chip systems for fast readout of local chemical and physical process parameters. Citing Literature Volume214, Issue9September 20171600921 RelatedInformation