Direct covalently functionalized carbon substrates with macromolecular cobalt phthalocyanine for advanced bisphenol a detection

초록

Bisphenol A (BPA) is an acknowledged endocrine disruptor, posing a risk to both human health and the environment. In the presented study, a covalently integrated tetraamino cobalt phthalocyanine-multi-walled carbon nanotubes (TACoPc-MWCNT) nanocomposite was designed as an advanced electrochemical sensing platform for BPA detection. The TACoPc macrocycle was synthesised via cyclotetramerization and subsequently covalently grafted onto MWCNTs through a Gomberg-Bachmann reaction. Unlike many recently reported systems that rely on physical adsorption, molecular imprinting, enzyme immobilization, or noble-metal nanoparticles, the proposed architecture ensures highly redox active, improved charge transport, robust interfacial coupling, long-term chemical and electrochemical stability. Fourier-transmission infrared spectroscopy (FTIR), X-ray diffraction (XRD), and UV-Visible spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) have been implemented to perform comprehensive structural and morphological characterisations. The conductive nanotube network and the redox-active cobalt centre work in cooperation to dramatically boost electron transfer and catalytic activity. Electrochemical examinations undertaken via cyclic voltammetry (CV), scan rate assessments, square wave voltammetry (SWV), and electron impedance spectroscopy (EIS) revealed a substantial oxidation peak at 0.54 V, supporting superior redox activity and stronger charge-transfer kinetics of the composite towards BPA sensing. The TACoPc-MWCNT modified sensor displayed a detection limit of 0.3 mu M, over a wide response range of 2.0 mu M to 20 mu M, and high sensitivity of 9.06 mu A/mu M cm(-2). Regardless of the presence of common interferents, the modified electrode achieved exceptional stability, reproducibility, and selectivity. Furthermore, the practical reliability of the modified electrode was authenticated by real sample analysis of tainted river water, with impressive recovery rates (>99%). Overall, the present study focuses on a stable, transition metal-based-macrocycle, covalently engineered nanocomposite electrode that offers a green, economical, and highly reliable electrocatalyst for trace-level BPA detection, highlighting its strong potential for environmental sensing and water-quality monitoring.

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