Transparent Carbon Ultramicroelectrode Arrays: Figures of Merit for Quantitative Spectroelectrochemistry for Biogenic Analysis of Reactive Oxygen Species

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• 作者：Jonathon Duay ; Janine Elliott ; Jason B. Shear ; Keith J. Stevenson
• 刊名：Analytical Chemistry
• 出版年：2015
• 出版时间：October 6, 2015
• 年：2015
• 卷：87
• 期：19
• 页码：10109-10116
• 全文大小：422K
• ISSN：1520-6882

文摘

Opaque and transparent carbon ultramicro- to nanoelectrode arrays were made using a previously reported facile versatile fabrication method (Duay et al. Anal. Chem. 2014, 86, 11528). First, opaque carbon ultramicroelectrode arrays (CUAs) were characterized for their analytical response to hydrogen peroxide (H₂O₂) oxidation using cyclic voltammetry. The alumina blocking layer was found to contribute to the noise and thus had undesirable effects on the array鈥檚 limit of detection (LOD) for H₂O₂ at fast scan rates. Nonetheless, at slower scan rates (谓 鈮?250 mV s^鈥?), the LODs for H₂O₂ for both opaque (O-CUAs) and transparent arrays (T-CUAs) were found to be lower than previously reported levels for array-based UMEs. LODs as low as 35 nM H₂O₂ are obtained for T-CUA at a 2.5 mV s^鈥? scan rate. Furthermore, the transparent arrays were analyzed for their spectroelectrochemical response during the oxidation/reduction of ferrocenemethanol. Results showed very good correlation between the optical and electrochemical response for ferrocenemethanol at a UV wavelength of 254 nm. Thus, these electrodes allow for the in situ mechanistic and kinetic characterization of heterogeneous electrochemical and intermediate homogeneous chemical reactions with high electroanalytical sensitivity, low detection limits, and wide dynamic range.