Quantitative trace level voltammetry in the presence of electrode fouling agents: Comparison of single-walled carbon nanotube network electrodes and screen-printed carbon electrodes

P.E., Sharel, Miller, Thomas S., Meng, Lingcong , Unwin, Patrick R. and Macpherson, Julie V. (2020) Quantitative trace level voltammetry in the presence of electrode fouling agents: Comparison of single-walled carbon nanotube network electrodes and screen-printed carbon electrodes. Journal of Electroanalytical Chemistry, 872 . p. 114137. ISSN 1572-6657

Full content URL: https://doi.org/10.1016/j.jelechem.2020.114137

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Item Type:Article
Item Status:Live Archive

Abstract

Single walled carbon nanotube (SWNT) network electrodes, in which a planar arrangement of SWNTs on an inert surface serve as a working electrode for voltammetry, offer considerable attributes for electroanalysis. Here, the effect of SWNT network density on the trace voltammetric analysis of a water-soluble ferrocene derivative (FcCOOH) is investigated in the presence of polyethylene glycol (PEG) or albumin, species that can foul (block) an electrode via adsorption. Fc-based analytes typically find use in redox labelling or redox shuttling, point-of-care electrochemical detection devices. Comparison is made between SWNT electrodes, grown by catalyzed chemical vapour deposition at three different surface coverages, 5, ~20 and ~30 μmSWNT μm-2, and commercial screen-printed carbon electrodes (SPCEs). In the presence of PEG (8% 2 K), for cyclic voltammetry, the lowest detectable concentration decreases as SWNT network density decreases. However, when employing differential pulse voltammetry, all three networks show a 1 nM FcCOOH limit of detection, three orders of magnitude smaller than achievable with SPCEs. This is attributed to the low capacitance of the SWNTs and absence of amorphous carbon structures which can contribute a pseudo-capacitive response. For both polyethylene glycol (PEG) and albumin (4%), repeat cycling shows the higher density SWNT network electrodes (≥20 μmSWNT μm-2) are far less susceptible to electrode fouling. Toward practical devices, a three-electrode chip, similar in design to that used in SPCEs, but using high density SWNT network electrodes, is also demonstrated to have impressive detection sensitivity for FcCOOH (nM level) in PEG solutions. The simplicity and practicality of the design widens the potential applications of these ultra-sensitive diagnostic tools based on planar network SWNTs.

Keywords:Single walled carbon nanotubes, Nanomolar detection, Differential pulse voltammetry, Albumin, Polyethylene glycol, Screen printed carbon electrode, Electroanalysis, Electrode fouling, Blocking
Divisions:College of Science > School of Chemistry
ID Code:47279
Deposited On:18 Nov 2021 10:52

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