doi:10.1016/j.elecom.2003.10.019 
Copyright © 2003 Published by Elsevier Science B.V.
A multi-electrode probe for parallel imaging in scanning electrochemical microscopy
Anna L. Barker
, 
, a, Patrick R. Unwina, Julian W. Gardnerb and Hugh Rieleyc
a Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
b School of Engineering, University of Warwick, Coventry CV4 7AL, UK
c Unilever Research Port Sunlight Laboratory, Quarry Road East, Bebington, Wirral L63 3JW, UK
Received 28 August 2003;
revised 20 October 2003;
accepted 20 October 2003. ;
Available online 13 November 2003.
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Abstract
The first use of a parallel (multiple data acquisition) electrode probe for amperometric imaging in scanning electrochemical microscopy (SECM) is described. A 16-electrode linear microdot device has been designed based on an array of 10 μm diameter disc electrodes with a pitch of 120 μm, that are individually addressable. This configuration leads to essentially no overlap of diffusion fields when this electrode is used for amperometric detection. Linear sweep voltammetry, together with fluorescence confocal laser scanning microscopy, has been used to assess the characteristics of the device. To demonstrate the possibilities of parallel imaging in SECM, we report use of the device to image a heterogeneous substrate with conducting and insulating features.
Author Keywords: Scanning electrochemical microscopy; Microdisc assay; Electrochemical imaging; Fluorescence confocal laser microscopy
Fig. 1. Photograph of a linear array used for SECM imaging. (a) 10 μm diameter Pt microdots on a 16-electrode linear array. This figure shows exposed Au bonding wire connecting the contact pads on the device and on the PCB. (b) Optical micrograph of a microdot on the same device.
Fig. 2. Substrate used in test SECM imaging experiments produced by sealing a bundle of 50 μm Pt wires in glass.
Fig. 3. Schematic showing the SECM set up used for parallel imaging.
Fig. 4. Linear sweep voltammograms recorded at 10 mV s
−1 for the reduction of 10 mM Ru(NH
3)
63+ in 0.2 M KCl at a linear array of sixteen 10 μm diameter Pt discs.
Fig. 5. (a) Linear sweep voltammograms recorded at 10 mV s
−1 for the reduction of 1 mM benzoquinone in 8 μM disodium fluorescein solution at 4 microdot electrodes of a linear array and (b) CLSM images of fluorescence profiles (image size 566 μm × 344 μm) for the four microdot electrodes recorded at the potentials shown.
Fig. 6. SECM image of the substrate shown in
Fig. 2 acquired in feedback mode using a 10 μm diameter Pt, RG=10, UME tip. The tip current is normalised relative to the current measured at the tip in bulk solution,
i(∞)=16.2 nA.
Fig. 7. SECM image of the substrate shown in
Fig. 2, acquired simultaneously at 5 electrodes on the linear array, scanned in a direction perpendicular to long axis of device. Normalisation of the current at each microdisc is based on the individual responses of the electrodes in bulk solution.
Abstract
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