Glucose, Fructose and H2O2 Detection by Microstructured Copper and Cobalt Oxides Electrodeposited onto Glassy Carbon Electrodes using Potentiostatic or Potentiodynamic Methods

Abstract

Copper or cobalt oxides were potentiostatically or potentiodynamically electrodeposited onto glassy carbon electrodes (GCE), and their activities in the electrooxidation of glucose, fructose and H2O2 were compared. Pourbaix diagrams, including acid-base, solubility, mono and polynuclear complex formation equilibria, were calculated to evaluate the most suitable conditions for electrodeposition, which were subsequently verified by voltammetric studies. The magnitude and duration of the potential pulses, potential range, and temperature were studied to determine a maximum sensitivity toward glucose, fructose or H2O2. The metal oxide-modified GCE was morphologically and chemically characterized by scanning electron microscopy (SEM/SEM–EDS) and used to determine the glucose content in pharmaceutical and synthetic aqueous solutions with satisfactory results. Our simple metal oxide-modified electrodes show sensitivity values that are similar (1929.7 μA mM-1 cm-2 for glucose using a Cu2O/GCE) to those obtained using other, more complex modified electrode architectures reported in the literature and also show sufficiently low limits of detection (60 < μM) for eventual application in glucose analysis of real samples