Molecularly Imprinted Magnetic Fluorescent Carbon Dots Using Polydopamine with Dual Functionality as a Monomer and Cross-Linking Agent for Selective Mefenamic Acid Detection

This research presents a sustainable and efficient method for synthesizing polydopamine imprinted magnetic carbon dots (MCDs@PI), which were synthesized from wheat straw via hydrothermal carbonization. The carbon dots were magnetically functionalized using iron salts and coated with a polydopamine layer, where dopamine acted as a functional monomer as well as a cross-linker. The sensor demonstrated high selectivity and sensitivity for mefenamic acid, achieving a limit of detection of 2.59 nM and a linear range of 13-103.6 nM (<i>R</i>² = 0.993). Recovery studies in spiked tap and river water samples showed excellent accuracy, with recoveries ranging from 98.72 to 100.80% and %RSDs between 1.08 and 3.79%, respectively. In pharmaceutical tablet analysis, recoveries ranged from 96.44 to 98.08% (%RSD: 3.25-4.03%). Moreover, the current approach exhibits a BAGI score of 75. These results underscore the potential of MCDs@PI as a robust, selective, and sustainable platform for trace-level detection of pharmaceutical pollutants in complex matrices.