Spectroscopic mechanism-driven design of a magnetic metal-organic framework (M-MXene@Fe-BTC) electrochemical sensor for detection of bisphenol A in water.

Bisphenol A (BPA), a persistent endocrine-disrupting compound, continues to accumulate in aquatic systems, underscoring the need for reliable monitoring tools. In this study, a magnetic MXene/Fe-BTC composite was integrated onto a screen-printed carbon electrode (M-MXene@Fe-BTC@SPCE) to create an electrochemical sensor capable of detecting BPA with high sensitivity in complex water matrices. The composite's hierarchical structure combining the conductivity of MXene, the magnetic responsiveness of Fe3O4, and the adsorption properties of Fe-BTC enabled efficient electron transfer and strong analyte affinity. Differential pulse voltammetry revealed a wide linear detection range of 1.5-436 µM, a low limit of detection of 0.15 µM, and a sensitivity of 0.46 µA µM-1 cm-2. Mechanistic insights obtained from high-resolution XPS showed that BPA recognition is facilitated by π-π stacking and hydrogen-bond interactions involving CC, C-OH, O-Fe, and OC-O groups, with additional spectral shifts in Fe 2p suggesting coordination effects between BPA and iron centers. The sensor also exhibited excellent repeatability (RSD = 1.54%) and maintained strong selectivity in the presence of common co-existing contaminants. Taken together, these findings demonstrate the capability of the M-MXene@Fe-BTC@SPCE sensor to provide fast and reliable BPA detection in environmental waters.