Bisphenol A sensing using carbon fibre transducers with and without metal-organic frameworks modification: towards greener tools for fish safety and surveil ecosystems

Bisphenol A (BPA) is widely used in plastic production; however, it has raised concerns about its human health implications and presence in aquatic ecosystems, as it is also known as an endocrine-disrupting compound. Given the urgency of developing eco-friendly monitoring tools, this study proposes and compares two novel green sensing platforms based on carbon paper (CP) for the determination of BPA in fish samples. One consists in the modification with a leaf-like shape zeolitic imidazolate framework (CP/ZIF-L), by a simple and water-based synthesis at room temperature, and the other uses a bare CP electrochemically pre-treated with sulfuric acid (CPP). Both sensors were morphologically and electrochemically characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, cyclic voltammetry and differential pulse voltammetry, and their greenness assessed by GAPI, Eco-scale and AGREE metrics. Under the optimum conditions, CP/ZIF-L and CPP exhibited a limit of detection of 15 ± 0.01 and 86 ± 2.9 nmol L^-1, as well as a linear range over BPA concentration up to 1 μmol L^-1 and 2 μmol L^-1 with sensitivity up to 53.80 ± 0.17 and 31.62 ± 0.35 μA (μmol L^-1) cm^-2, respectively, confirming the superiority in performance of the MOF-based sensor for BPA detection. Upon validation in fish samples, both sensors achieved excellent accuracy (92.5 ± 5.9-103.1 ± 4.6 %), repeatability (4.1-5.7 %), reproducibility (7.1-7.3 %) and selectivity towards organic and inorganic interferents (-2.8-8.8 %). The sensors demonstrated superior greenness metrics compared to the traditional chromatographic method. Altogether, the results highlight the environmental friendliness, reliability and potential of the proposed sensors as green tools for BPA monitoring in complex environmental and food samples.