Scanning electrochemical microscopy. 19. Ion-selective potentiometric microscopy

Horrocks, Benjamin R.; Mirkin, Michael V.; Pierce, David T.; Bard, Allen J.; Nagy, Géza; Tóth, Klára

doi:10.1021/ac00057a019

Cited by 217 publications

(145 citation statements)

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“…When deployed as the tip in scanning electrochemical microscopy (SECM), these electrodes have enabled the measurement of pH with high spatial resolution at interfaces. [11][12][13][14] The scale on which pH electrodes can be made has advanced in recent years to the micro 15,16 and nano scale. 17,18 SECM pH probes employing a variety of metal/metal oxides have been reported previously.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Dual Function Nanoscale pH-Scanning Ion Conductance Microscopy (SICM) Probes for High Resolution pH Mapping

et al. 2013

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(2013) Fabrication and characterization of dual function nanoscale pH-scanning ion conductance microscopy (SICM) probes for high resolution pH mapping. Analytical Chemistry, Volume 85 (Number 17). pp. 8070-8074 Permanent WRAP url: http://wrap.warwick.ac.uk/57249 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work of researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-forprofit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work http://dx.doi.org/10.1021/ac401883n The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. AbstractThe easy fabrication and use of nanoscale dual function pH-scanning ion conductance microscopy (SICM) probes is reported. These probes incorporate an iridium oxide coated carbon electrode for pH measurement and an SICM barrel for distance control, enabling simultaneous pH and topography mapping. These pH-SICM probes were fabricated rapidly from laser pulled theta quartz pipets, with the pH electrode prepared by in-situ carbon filling of one of the barrels by the pyrolytic decomposition of butane, followed by electrodeposition of a thin layer of hydrous iridium oxide. The other barrel was filled with an electrolyte solution and Ag/AgCl electrode as part of a conductance cell for SICM. The fabricated probes, with pH and SICM sensing elements typically on the 100 nm scale, were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and various electrochemical measurements. They showed a linear super-Nernstian pH response over a range of pH (pH 2-10). The capability of the pH-SICM probe was demonstrated by detecting both pH and topographical changes during the dissolution of a calcite microcrystal in aqueous solution. This system illustrates the quantitative nature of pH-SICM imaging, because the dissolution process changes the crystal height and interfacial pH (compared to bulk) and each is sensitive to the rate. Both measurements reve...

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Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Dual Function Nanoscale pH-Scanning Ion Conductance Microscopy (SICM) Probes for High Resolution pH Mapping

et al. 2013

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“…As an application of this method, the pH distribution around the metal electrodes during water reduction and during corrosion was imaged with a relatively short time scale. 12 These present methods have a higher spatial and time resolution than our presented pH-imaging microscope. However, our pH-imaging microscope requires neither scanning of the sensing probe in side the sample nor the addition of a pH-sensitive fluorescent dye.…”

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confidence: 83%

“…One method uses a scanning electrochemical microscope (SECM) 12 with a miniaturized ion-selective potentiometric electrode as a sensing probe. As an application of this microscopy, a wide variety of reactions, such as corrosion, enzyme, and cell metabolism, were presented.…”

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confidence: 99%

Observation and Evaluation of Proton Diffusion in Porous Media by the pH-Imaging Microscope Using a Flat Semiconductor pH Sensor

et al. 2002

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We have been developing a pH-imaging microscope using a flat semiconductor pH sensor based on photocurrent characteristics of semiconductor silicon, which we call a Scanning Chemical Microscope. [1][2][3][4][5][6][7][8][9] The sensor utilized in this microscope functions by light illumination to the opposite side of pH sensing. 10 The sensor also functions as an array of multiple pH sensing parts by focussing and scanning the light illumination two dimensionally.The pH values obtained at each pHmeasurement point on the sensor are converted to a color scale, and the color scale of each pH value is displayed as pH images by the microscope. Taking advantage of the use of the sensor with a flat pH-sensing surface and capability of multiple-point pH measurement, we have demonstrated a new type of surface characterization of solid samples using this microscope. [3][4][5] In this characterization, a thin agar film is placed on the flat sensor with the sample surface contacting the top of the agar film. Multiple-point pH measurements enable the pH distribution formed in the agar film to be imaged. Since the pH distribution in the agar film was formed by the contact of the sample to the agar film, the pH image reflects the surface chemical condition of the sample. Thus, the surface chemical information of the sample can indirectly be obtained. As an application of this unique surface analysis, we successfully imaged the surface of some biological samples, such as plant leaves and sliced human teeth. We also visualized the generation and expansion of electrochemically formed pH distributions while taking advantage of the use of a sensor with a flat pH-sensing surface and the capability of multiple-point pH measurements in this microscope. 2 Simple electrolysis was conducted in agar film formed on the flat sensor using a platinum anode and cathode.The resulting lower and higher pH regions and their expansions were repeatedly visualized. Iwasaki et al. also conducted similar experiments in solutions with high viscosity, evaluating the diffusion coefficients of protons and hydroxide in solution with various viscosities. 9 In this research, we successfully observed proton diffusion in a porous environment using our pH-imaging microscope. The porous environment was formed by packing small particles on the flat sensor of the microscope with an electrolyte solution. Such an environment is regarded as an imitated soil system; thus, the observation of proton diffusion in the soil system was estimated in this research. The pH distribution formed in the bottom of the layer was repeatedly imaged after adding acid droplets on the top of the particle packed layer. The set of pH images obtained by repeated imaging showed the difference in the diffusion characteristics of acid inside the packed particle layer. 11In addition, these pH images allowed the effective diffusion coefficient of the acid, which was an important parameter in diffusion in porous media, to be calculated combined with a simple mathematical method.Some other pH-imagin...

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“…Taking pH determination as an example one finds different solid state electrodes such as antimony oxide (Horrocks et al, 1993), iridium oxide (Marzouk et al, 1998;Wipf et al, 2000;Bezbaruah and Zhang, 2002;Hassan et al, 2002), tungsten oxide or palladium hydride (Imokawa et al, 2006) which provide a Nernstian response with pH. Many potential selective electrodes rely on solid state membranes to provide selectivity.…”

Section: Potential Selective Electrodesmentioning

confidence: 99%

Electrochemical techniques and sensors for ocean research

Denuault

2009

Ocean Sci.

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Scanning electrochemical microscopy. 19. Ion-selective potentiometric microscopy

Cited by 217 publications

References 10 publications

Fabrication and Characterization of Dual Function Nanoscale pH-Scanning Ion Conductance Microscopy (SICM) Probes for High Resolution pH Mapping

Fabrication and Characterization of Dual Function Nanoscale pH-Scanning Ion Conductance Microscopy (SICM) Probes for High Resolution pH Mapping

Observation and Evaluation of Proton Diffusion in Porous Media by the pH-Imaging Microscope Using a Flat Semiconductor pH Sensor

Electrochemical techniques and sensors for ocean research

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