Effect of cytosine and adenine on graphene oxide for the sensing of dopamine: Electrochemical and theoretical studies

• Published in: Microchemical journal 2024-11, Vol.206, p.111518, Article 111518
• Main Authors: Zhao, Yulin, Kumar, Mohan, Freiberger, Markus, Kudur Jayaprakash, Gururaj, Wang, Miao, Reddy, Sathish, Yang, Chenxin, Zhao, Wei
• Format: Article
• Language: English
• Subjects: Adenine; Cytosine; Dopamine; Frontier molecular orbitals; Graphene oxide
• ISSN: 0026-265X
• DOI: 10.1016/j.microc.2024.111518

[Display omitted] •Cytosine (CY) and adenine (AD) functional groups were introduced on the graphene oxide (GO).•The prepared functionalized GOs were used as a modifier in the carbon paste electrode (CPE) for the determination of dopamine (DA).•A lower limit of detection of 9 nm and 7 nm were found at the CY and AD functionalized GO CPE, respectively.•Theoretical concepts were utilized to investigate redox electron transfer reactive sites on the CY and AD.•Recognized the oxidation and reduction capacity of CY and AD for DA sensing. In this work, the electrochemical interaction between dopamine and cytosine/adenine on the graphene oxide (GO) is elucidated by quantum chemical simulation methods. Initially, GO, cytosine-functionalized GO (CGO), and adenine-functionalized GO (AGO) were prepared, and then utilized for the carbon paste electrode (CPE) modification. The as-prepared CGO-modified CPE (CGCPE) and AGO-modified CPE (AGCPE) were applied for the electrochemical sensing of dopamine (DA), and the obtained consequences illustrate the improved sensitivity of modified CPEs (MCPEs) compared to bare CPE (BCPE). Here, applied theoretical concepts based on analytical Fukui functions and frontier molecular orbitals (FMO) for cytosine and adenine functional groups in order to find active sites, and explained with evidence for the detection of DA by enhancing sensitivity. Moreover, the AGCPE has been shown higher electrochemical response compared to CGCPE for the detection of DA, and this result also agreed with theoretically from Global electron transfer results. The MCPEs were also utilized to examine the different electrochemical parameters and determine the DA concentration in the nanomolar range. The detection limit for CGCPE and AGCPE was found to be 9 nm and 7 nm, respectively.