Glassy carbon and other carbon polymorphs are commonly utilized as electrodes to detect redox-active biomolecules but are limited by the modest electron-transfer kinetics that are inherent to the electronic work function of carbons. Conformally modifying the interface of carbon electrodes with a nanoscopic coating of ruthenium(IV) oxide (RuO2) is an alternative way to increase carbon’s electron-transfer kinetics using only trace amounts of a precious metal resource. In this work, we studied the influence of nanocrystalline RuO2 on pyrolytic carbon to electrochemically detect 1 nM – 10 mM concentrations of the neurotransmitter dopamine under acidic conditions. Carbon films were deposited by pyrolyzing a stream of dilute (~20 wt.%) benzene vapor in Ar(g) at 1000&lt;span style=font-size:10.8333px"&gt; °&lt;/span&gt;C onto planar quartz substrates. We functionalized the surface of carbon electrodes with ruthenium(IV) tetroxide under non-aqueous, cryogenic conditions, and the resulting ruthenia-modified pyrolytic carbon electrodes were calcined to 250&lt;span style="font-size:10.8333px"&gt; °&lt;/span&gt;C and then tested in a three-electrode electrochemical cell configuration using cyclic voltammetry and differential pulse voltammetry. Ruthenia-modified electrodes demonstrated a greater analytical sensitivity (1.71(± 0.03)×106 µA M–1 vs. 9.4(± 0.2)×105 µA M–1) and a lower limit of detection (5(± 6)×10–8 M vs. 6(± 9)×10–7 M) than unmodified pyrolytic carbon electrodes. Future experiments will determine the electrochemical stability of these electrodes to repeated cycling and will explore their utility for detecting dopamine and other biologically important molecular species under physiological conditions.

How low can they go: Detecting dopamine on ruthenia-modified pyrolytic carbon electrodes

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.