Synergistic NH₂-MIL-101(Fe)/thermally reduced graphene oxide composite integrated voltammetric sensor for carcinogenic chrysene in particulate matter

Atmospheric particulate matter (PM) containing polycyclic aromatic hydrocarbons (PAHs) poses serious health risks due to its carcinogenic nature. Chrysene (CHR), a priority pollutant known for its toxicity and persistence, necessitates the development of sensitive and cost-effective detection methods. In this study, we report, for the first time, a highly sensitive voltammetric sensor for CHR detection using a composite of NH₂-MIL-101(Fe) and thermally reduced graphene oxide (TRGO) modified glassy carbon electrode (NH₂-MIL-101(Fe)/TRGO/GCE). The composite was prepared via ultrasonication of TRGO with NH₂-MIL-101(Fe) and synthesized using a microwave-assisted method. Comprehensive physicochemical characterization, including various spectroscopic and electrochemical measurements alongside thermogravimetry and N₂ adsorption isotherms, confirmed the composite's crystallinity, high porosity, and conductivity. Under optimal conditions, the NH₂-MIL-101(Fe)/TRGO/GCE sensor achieved a low limit of detection (0.037 µM), high sensitivity (0.345 µA µM⁻¹), and a wide linear detection range (0.1–240 μM). The sensor demonstrated superior selectivity for CHR, even in the presence of other carcinogenic PAHs, including naphthalene, phenanthrene, fluorene, pyrene, and benzo[a]pyrene. These impressive attributes were primarily due to the synergistic effects of the composite, including strong π-π interaction and rapid electron transfer. Furthermore, the sensor showed excellent selectivity, reproducibility, and high recovery rates when applied to CHR detection in complex PM samples and other contaminant sources such as soil and river water. These results demonstrate the NH₂-MIL-101(Fe)/TRGO/GCE sensor as a promising technology for pollutant analysis and environmental monitoring in practical applications.