Triple-synergistic Mn-MOF electrochemical sensor for multiplex antibiotic detection: A robust and stable platform for food safety monitoring

Abstract

The excessive use of nitrofurantoin (NFT), nitrofurazone (NFZ), tetracycline hydrochloride (TC), and chloramphenicol (CAP) poses significant health risks due to their toxicity. Existing detection methods are limited in sensitivity and portability, which hinders rapid on-site monitoring of antibiotic residues contemporary livestock production. This study introduces an electrochemical sensor based on {[Mn₂(BPTC)(DMA)₂(H₂O)₂]·DMA}_n (SXNU-2-Mn) (H₄BPTC = biphenyl-3,3′,5,5′-tetracarboxylic acid, DMA = N, N-Dimethylacetamide, SXNU = Shanxi Normal University). The Metal-organic frameworks (MOFs) SXNU-2-Mn features a three-dimensional PtS topology with a unique pore microenvironment containing hydroxyl oxygen groups and DMA molecules, along with its manganese (Mn) catalytic center. The rod-shaped nanometer array of pristine SXNU-2-Mn/GCE sensor demonstrates exceptional performance in detecting and differentiating multiple antibiotics, including NFT, NFZ, TC, and CAP, each with distinct redox potential. Notably, for CAP, the sensor exhibits an extensive linear range from 0.07 to 900.00 μM and an exceptionally much lower limit of detection (LOD) of 19.45 nM. Stability assessments indicate that the sensor retains over 94.6 % of its initial performance after seven days, with a variation of less than 2.4 % for CAP detection. The pore environment facilitates a triple-synergistic smart recognition mechanism for CAP, involving π-π stacking, hydrogen bonding, and Mn(II)-mediated catalytic interactions. The practical applicability of the SXNU-2-Mn/GCE sensor was validated through real-world food samples such as chicken and milk, achieving recovery rates ranging from 95.45 % to 108.10 %. This research presents a pristine MOF platform that integrates molecular recognition and redox catalysis, offering a portable solution for simultaneous antibiotic residue detection and advancing food safety monitoring technologies.