Amperometric microsensor based on nanoporous gold for ascorbic acid detection in highly acidic biological extracts

Author(s)

Kumar, Abhishek ^[1] ; Furtado, Vinicius L. ^[1] ; Goncalves, Josue M. ^[1] ; Bannitz-Fernandes, Renata ^[2] ; Netto, Luis Eduardo S. ^[2] ; Araki, Koiti ^[1] ; Bertotti, Mauro ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Chem, Dept Fundamental Chem, Av Prof Lineu Prestes 748, BR-05513970 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Biosci, Dept Genet & Evolutionary Biol, Rua Matao 321, BR-05508090 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Analytica Chimica Acta; v. 1095, p. 61-70, JAN 25 2020.
• Web of Science Citations: 0

Abstract

Tuning the electrocatalytic properties of high surface area porous metallic frameworks like Nanoporous Gold (NPG) by tailoring the structure is a convenient strategy to design electrochemical sensors. Accordingly, an NPG-based sensitive, selective and robust electroanalytical platform was designed for the detection of ascorbic acid (AA) in acidic extracts of Aspergillus fumigatus fungus and Arabidopsis thaliana leaves. NPG films were electrodeposited on a gold microelectrode by potentiostatic electrodeposition and characterized by electron microscopy techniques, which confirmed the morphology and highly porous structure resembling nanowires-type pure gold fractals. The electrodeposition parameters, particularly deposition potential and time, were optimized to achieve large and selective amperometric detection of AA on the NPG modified electrodes. Faster electron transfer kinetics was manifested on the 0.3 V shift in overpotential and remarkable enhancement of the oxidation peak current as compared with bare gold electrode. Amperometric measurements were performed at 0.3 V vs. Ag/AgCl((sat. KCI) )in the highly acidic electrolyte solution employed to extract ascorbate from biological samples and minimize its autoxidation. The sensitivity of conventional Au-microelectrodes was increased about one thousand-fold upon modification with NPG film, reaching 2 nA mu mol(-1) L-1. The detection limit for AA based on a linear current-concentration calibration plot was found to be 2 mu mol L-1. The NPG-based microsensor was demonstrated to be selective, reproducible and stable, and was employed for determinations of AA concentration in highly acidic biological extracts. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 18/08782-1 - Miniaturized and integrated chemical sensors: new fabrication platforms for biological, clinical and environmental applications
• Grantee: Mauro Bertotti
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/21489-1 - Supramolecular nanotechnology: design, materials and devices
• Grantee: Henrique Eisi Toma
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/09027-2 - Fabrication of electrochemical sensors for ascorbate detection in the human pathogenic fungus Aspergillus fumigatus
• Grantee: Vinícius Lima Furtado
• Support Opportunities: Scholarships in Brazil - Scientific Initiation