Electrochemical Transformation of Thiol-Iodine-Based Reactions toward Multiplexed Sensing Applications for Plant-Stress Hormone and Environmental Contaminant

Abstract

Functionalized thiophenes are potential electroactive species that serve as efficient molecular electrochemical sensors. This work describes the fabrication of a 3-thiophene acetic acid (TAA)-modified screen-printed carbon electrode/multi-walled carbon nanotube (SPCE/MWCNT) platform via a facile electrochemical method in an aqueous medium. The effectual PT-Redox (product of TAA formed postpotentiostatic polarization) integration over SPCE/MWCNT was confirmed through various spectroscopic and electrochemical investigations. The SPCE/MWCNT showcased exceptional interaction with PT-Redox, creating a resilient platform for its precise binding, thereby enhancing the electrode–electrolyte electroactive region, topographic roughness, electron conductivity, host response, and comprehensive electrochemical properties. The as-prepared electrode (SPCE/MWCNT@PT-Redox) was employed for the selective detection and quantification of glutathione (GT) as well as hydrazine (HyD) in an aqueous medium. The sensor showed excellent electrocatalytic oxidation responses toward these analytes, yielding a good sensitivity of 0.32 μA mM^–1, a low detection limit (D_L) of 0.225 μM, a broad linear dynamic window of 0–400 μM for GT, a high sensitivity of 0.13 μA mM^–1, a low D_L of 0.56 μM, and a linear window of 0–350 μM for HyD, obtained via the differential pulse voltammetry (DPV) technique. This substantiates that the modification with PT-Redox significantly boosted the electrode’s interfacial activity and catalytic potential. Furthermore, the electrode exhibited robust antifouling and anti-interference traits, suggesting the composite’s enhanced stability and sensing capabilities for real-world applications. The captivating features, including excellent specificity, fast response dynamics, and simple sample preparation necessities of the proposed system, reveal a promising platform that accomplishes significant potential in futuristic sensing applications.