Umi Fazara Md Ali
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Preferred name
Umi Fazara Md Ali
Official Name
Umi Fazara, Md Ali
Alternative Name
Ali, Umi Fazara Md
Md. Ali, Umi Fazara
Umi Fazara, M. A.
Main Affiliation
Scopus Author ID
57195513638
Researcher ID
AAU-4840-2020

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  • Publication
    Renewable non-enzymatic copper-based surfaces for the detection of glucose, fructose, sucrose, and galactose
    (Elsevier, 2025-03)
    Adam Tan Tiek Aun
    ;
    Noordini Mohamad Salleh
    ;
    Umi Fazara Md Ali
    ;
    Wan Jefrey Basirun
    ;
    Yu-Shu Chiang
    ;
    Ninie Suhana Abdul Manan
    This study aims to circumvent the environmental and logistical drawbacks of disposable electrode strips by developing Cu-based sugar sensors that can be renewed for use. In this work, Cu-based sugar sensors were prepared through the electrodeposition of CuAg or lactate-templated Cu onto a carbon paste electrode (CPE) followed by electrochemical oxidation in a sodium hydroxide solution. Users can perform this process themselves by using a pre-programmed power supply and following the provided instructions. Important synthesis parameters were initially screened using experiments with a 2k factorial design to identify the most crucial factors that affect the performance of the sugar sensor. Optimization was conducted using a central composite design when necessary. An optimal lactate-templated Cu oxide-based sugar sensor with an average sensitivity of 523 µA cm2 mM−1 and an optimal CuAg oxide-based sugar sensor with a sensitivity of 191 µA cm2 mM−1 are obtained. Cyclic voltammetry (CV) analysis revealed that the oxidation rate of glucose on CuAg and lactate-templated Cu oxide-based sugar sensors is limited by surface kinetics. Electrochemical impedance spectroscopy (EIS) revealed that increasing glucose concentration in the electrolyte causes a decrease in charge transfer resistance (Rct). A higher glucose level results in better electron transfer and therefore a higher proportional current. Field emission scanning electron microscopy (FESEM) revealed that both CuAg and lactate-templated Cu oxide-based sugar sensors produced under optimized conditions also have better active material coverage and more uniquely shaped nanostructures. Energy-dispersive X-ray spectroscopy (EDX) analysis revealed that both the optimal CuAg oxide-based sugar sensor and the lactate-templated Cu oxide-based sugar sensor have a higher oxygen-to-copper ratio, which could positively influence their catalytic properties. The current density of both sensor types was found to decline over a period of 10 days. The CuAg oxide-based sugar sensor suffered an average drop of 27.10 % in current density and lactate-templated Cu oxide suffered an average drop of 31.4 % in current density. Additionally, when subjected to a constant potential of 0.5 V in a 6.04 mM glucose solution for 12 hours, both sensors displayed a significant decline in current density, 40.3 % for the CuAg oxide-based sugar sensor and 45.0 % for the lactate-templated Cu oxide -based sugar sensor. However, the sugar sensors can be renewed easily after each use, circumventing the issue of electrode stability.
      2  1
  • Publication
    Non-Enzymatic Glucose Sensors Involving Copper: An Electrochemical Perspective
    ( 2023)
    Aun Tan Tiek
    ;
    Noordini Mohamad Salleh
    ;
    Umi Fazara Md Ali
    ;
    Ninie Suhana Abdul Manan
    Non-enzymatic glucose sensors based on the use of copper and its oxides have emerged as promising candidates to replace enzymatic glucose sensors owing to their stability, ease of fabrication, and superior sensitivity. This review explains the theories of the mechanism of glucose oxidation on copper transition metal electrodes. It also presents an overview on the development of among the best non-enzymatic copper-based glucose sensors in the past 10 years. A brief description of methods, interesting findings, and important performance parameters are provided to inspire the reader and researcher to create new improvements in sensor design. Finally, several important considerations that pertain to the nano-structuring of the electrode surface is provided.
      2  23