An Electrochemical Nonenzymatic Microsensor Modified by CuCo2O4 Nanoparticles for Glucose Sensing

Abstract

This work reported a low-cost, highly sensitive nonenzymatic glucose sensor based on electrochemical electrode decorated by CuCo2O4 nanoparticles. The CuCo2O4 nanoparticles were synthesized by a hydrothermal method using oxalic acid and sodium hydroxide as precipitators. The results showed that the oxalate-assisted CuCo2O4 electrode exhibits excellent glucose sensing performance, including superb sensitivity to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4506.7 \mu \text{A} \cdot $ </tex-math></inline-formula> mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}\,\,\cdot $ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{2}}$ </tex-math></inline-formula> with the correlation coefficient of 0.99674, and the detection limit as low as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.446 \mu \text{M}$ </tex-math></inline-formula> , as well as extensive linear range from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1 \mu \text{M}$ </tex-math></inline-formula> to 10 mM, which is superior to that of the NaOH-assisted CuCo2O4. Additionally, the glucose sensor had a great selectivity and was not interfered by citric acid (CA), ascorbic acid (AA), dopamine (DA), urea, and so on. Moreover, it also showed good repeatability and long-term stability for up to 28 days. In alkaline solution, the synergistic action of bimetallic ions in CuCo2O4 promotes the electrooxidation of glucose. These findings prove that the oxalate-assisted CuCo2O4 is an advantageous electrode material for nonenzyme glucose sensors.