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Cyclic voltammetric and electrical impedance spectroscopy studies of graphene- and conductive polymer–based enzyme electrodes

Ismail, Nur Alya Batrisya and Ramli, Nurul Izzati and Abd-Wahab, Firdaus and Wan Salim, Wan Wardatul Amani (2019) Cyclic voltammetric and electrical impedance spectroscopy studies of graphene- and conductive polymer–based enzyme electrodes. International Journal of Integrated Engineering, 11 (3). pp. 70-80. ISSN 2229-838X E-ISSN 2600-7916

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Screen-printed carbon electrodes (SPCEs), modified with graphene oxide and poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid (GO-PEDOT:PSS/SPCEs), and SPCEs modified with partially reduced GO and PEDOT:PSS (prGO-PEDOT:PSS/SPCEs) were studied for electrochemical transduction. Randles-Sevcik analysis showed that the prGO-PEDOT:PSS/SPCE has a higher effective surface area of 219.3 μm2 in comparison to the unreduced GO-PEDOT:PSS/SPCE (87.0 μm2) and the bare SPCE (71.7 μm2). Using electrical impedance spectroscopy (EIS), we determined that the prGO-PEDOT:PSS/SPCE has a lower charge-transfer resistance (Rct) of 163.82 Ω in comparison to the GO-PEDOT:PSS/SPCE (427.87 Ω) and the bare SPCE (13.31 kΩ). Glucose oxidase (GOx) was immobilized on all electrode types, including GO/SPCE as additional control and tested with low (0.2 mM), intermediate (0.6 mM), and high (1 mM) glucose concentrations. GOx/GO/SPCEs showed the largest change in anodic peak current (Ipa), 8.5, 7.5 and 4.9 μA for low, intermediate, and high glucose concentrations, respectively. Interestingly, GOx/prGO-PEDOT:PSS/SPCEs have no change in both anodic and cathodic peak current, although they exhibit better redox capability, while GOx/SPCEs have very low Ipa. The results show that the high effective surface area and low charge-transfer resistance (Rct) of prGO-PEDOT:PSS/SPCEs do not necessarily result in a sensitive glucose sensor in cases where immobilization of enzymes on the material can affect electron transfer.

Item Type: Article (Journal)
Additional Information: 5236/74856
Uncontrolled Keywords: Cyclic voltammetry, electrical impedance spectroscopy, PEDOT:PSS, partially reduced graphene oxide, glucose oxidase, electrochemical transduction.
Subjects: Q Science > QD Chemistry
T Technology > TP Chemical technology > TP155 Chemical engineering
T Technology > TP Chemical technology > TP248.13 Biotechnology
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button): Kulliyyah of Engineering > Department of Biotechnology Engineering
Kulliyyah of Engineering
Depositing User: Dr Wan Wardatul Amani Wan Salim
Date Deposited: 03 Oct 2019 09:25
Last Modified: 03 Oct 2019 09:25
URI: http://irep.iium.edu.my/id/eprint/74856

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