Transparent carbon ultramicroelectrode arrays: figures of merit for quantitative spectroelectrochemistry for biogenic analysis of reactive oxygen species.
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's limit of detection (LOD) for H2O2 at fast scan rates. Nonetheless, at slower scan rates (ν ≤ 250 mV s(-1)), 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(-1) 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.
Department of Chemistry, Center for Nano and Molecular Science and Technology, The University of Texas at Austin , Austin, Texas 78712, United States.
Jonathon
J
Duay
Department of Chemistry, Center for Nano and Molecular Science and Technology, The University of Texas at Austin , Austin, Texas 78712, United States.
Janine
J
Elliott
Department of Chemistry, Center for Nano and Molecular Science and Technology, The University of Texas at Austin , Austin, Texas 78712, United States.
Jason B
JB
Shear
Department of Chemistry, Center for Nano and Molecular Science and Technology, The University of Texas at Austin , Austin, Texas 78712, United States.
Keith J
KJ
Stevenson
D002244:Carbon / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000295:instrumentation*; D006861:Hydrogen Peroxide / Q000032:analysis*; D057230:Limit of Detection; D008839:Microelectrodes; D010084:Oxidation-Reduction
D002244:Carbon; D006861:Hydrogen Peroxide