The Influence of Alumina Type on the Immobilization of Ascorbate Oxidase and Ascorbic Acid Detection

Authors

  • Barbara Ramadani University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12-16, P.O. Box 47, Belgrade, 11158, Republic of Serbia
  • Sonja Novaković University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12-16, P.O. Box 47, Belgrade, 11158, Republic of Serbia
  • Miloš Mojović University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12-16, P.O. Box 47, Belgrade, 11158, Republic of Serbia
  • Zorica Mojović University of Belgrade - Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, Belgrade, Republic of Serbia

Abstract

Two alumina types (trihydrate (T) and anhydrous (G)) were used for the immobilization of ascorbate oxidase (AO) by the adsorption procedure. The samples were characterized by FTIR analysis and EPR spectroscopy to confirm the presence of enzyme in the composite and the activity of immobilized enzyme. The samples of alumina with and without AO were used as modifer of carbon paste electrode and tested by Fe(CN6)3-/4- redox probe using cyclic voltammetry at different scan rates. The response of investigated electrodes toward ascorbic acid was tested in the Britton-Robinson buffer at pH range of 2 to 5. Direct detection of ascorbic acid was tested at G and G+AO electrodes and the calibration curves were constructed by square wave voltammetry under the optimized conditions. The immobilization of AO at anhydrous alumina increased the concentration range and the sensitivity from 0.00617 µM/µA for G to 0.01693 µM/µA for G+AO in the concentration range from 10 µM to 200 µM.

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Published

2025-06-03

Issue

Vol. 57 No. 1 (2025)

Section

Articles