Issue 13, 2016

Pencil it in: pencil drawn electrochemical sensing platforms


Inspired by recent reports concerning the utilisation of hand drawn pencil macroelectrodes (PDEs), we report the fabrication, characterisation (physicochemical and electrochemical) and implementation (electrochemical sensing) of various PDEs drawn upon a flexible polyester substrate. Electrochemical characterisation reveals that there are no quantifiable electrochemical responses upon utilising these PDEs with an electroactive analyte that requires an electrochemical oxidation step first, therefore the PDEs have been examined towards the electroactive redox probes hexaammineruthenium(III) chloride, potassium ferricyanide and ammonium iron(II) sulfate. For the first time, characterisation of the number of drawn pencil layers and the grade of pencil are examined; these parameters are commonly overlooked when utilising PDEs. It is demonstrated that a PDE drawn ten times with a 6B pencil presented the most advantageous electrochemical platform, in terms of electrochemical reversibility and peak height/analytical signal. In consideration of the aforementioned limitation, analytes requiring an electrochemical reduction as the first process were solely analysed. We demonstrate the beneficial electroanalytical capabilities of these PDEs towards p-benzoquinone and the simultaneous detection of heavy metals, namely lead(II) and cadmium(II), all of which are explored for the first time utilising PDEs. Initially, the detection limits of this system were higher than desired for electroanalytical platforms, however upon implementation of the PDEs in a back-to-back configuration (in which two PDEs are placed back-to-back sharing a single connection to the potentiostat), the detection limits for lead(II) and cadmium(II) correspond to 10 μg L−1 and 98 μg L−1 respectively within model aqueous (0.1 M HCl) solutions.

Graphical abstract: Pencil it in: pencil drawn electrochemical sensing platforms

Supplementary files

Article information

Article type
17 Feb 2016
25 May 2016
First published
26 May 2016
This article is Open Access
Creative Commons BY license

Analyst, 2016,141, 4055-4064

Pencil it in: pencil drawn electrochemical sensing platforms

C. W. Foster, D. A. C. Brownson, A. P. Ruas de Souza, E. Bernalte, J. Iniesta, M. Bertotti and C. E. Banks, Analyst, 2016, 141, 4055 DOI: 10.1039/C6AN00402D

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