Malays. J. Anal. Sci. Volume 29 Number 6 (2025): 1517

 

Research Article

 

Development of modified polyaniline-pencil graphite electrode (PANI/PGE) as a corrosion electrochemical sensor for the voltammetric detection of Fe2+ ions

 

Amalia Najihah Mahzan1, Hairul Hisham Hamzah2, Mohd Azam Osman3, Siti Fatimah Nur Abdul Aziz1*, and   M. Hazwan Hussin1*

 

1Materials Technology Research Group (MaTReC), School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia

2School of Health and Life Sciences, Teesside University, Middlesbrough, TS1 3BX, Tees Valley, England, United Kingdom

3School of Computer Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia

 

*Corresponding author: mhh@usm.my; fatimahnuraa@usm.my

 

Received: 17 March 2025; Revised: 9 September 2025; Accepted: 24 September 2025; Published: 28 December 2025

 

Abstract

This study has developed a pencil graphite electrode (PGE), modified with polyaniline (PANI), to serve as a simple, selective, and sensitive electrochemical sensor for the voltammetric detection of Fe2+ ions, specifically for quantifying iron in corrosion studies. The modification of PANI on the PGE (PANI/PGE) was performed through electropolymerization process by cyclic voltammetry (CV) in a potential range of –1 V to 1 V at a scan rate of 100 mV/s for 20 cycles. The active surface area was calculated to increased by 35% upon the modification. The CV and potentiodynamic polarization were utilized to study the anodic behaviour of the Fe2+ ions. The PANI/PGE exhibited good electrocatalytic activity and significantly enhanced peak current ratio of approximately 1.83 compared to the bare PGE, making it effective for determining the corrosion rate of mild steel. Parameters including electroactive surface area, the effect of scan rate, and sensitivity were investigated. The cyclic voltammogram of the PANI/PGE showed a good linearity in the concentration range 0.005 M to 0.05 M with the detection limit of of 1 ×10-2 M and quantification limit of 3×10-2 M. Notably, the PANI/PGE electrode demonstrated a higher detection of Fe2+ ions compared to the bare PGE electrode. Specifically, at 7 days, the current for the PANI/PGE electrode increased by 48%, while at 35 days, it increased by 32%, highlighting the enhanced performance of the modified electrode. The development of the modified PGE as an electrochemical sensor for detecting corrosion in mild steel has been successfully achieved. This study underscores the enhanced sensitivity and selectivity of the PANI-modified PGE, showcasing its potential for efficient on-site detection by quantifying Fe2+ ions in corrosion samples.

 

Keywords: mild steel; cyclic voltammetry; electrochemical sensor; pencil graphite electrode

 

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