A Cu-based catalytic molecularly imprinted electrochemical sensor on paper for phthalylsulfacetamide detection in environmental water

This work presents a disposable, integrated three-electrode sensor fabricated on paper via vacuum filtration of single-walled carbon nanotubes for rapid and sensitive detection of phthalylsulfacetamide (PSA) in environmental water. To improve performance, the working electrode was functionalized with a two-dimensional copper-based catalyst synthesized by one-pot pyrolysis, which provides high electrocatalytic activity. A molecularly imprinted polymer (MIP) layer was then constructed on the electrode surface through a dual-functional monomer strategy, generating specific recognition cavities complementary to PSA. The synergistic integration of the catalytic Cu-based material and the selective MIP enabled rapid, accurate, and sensitive PSA detection. Experimental results show a broad linear detection range (10 nM to 60 μM), a low detection limit (3.86 nM), good reproducibility (RSD of 3.9 %), good long-term stability (RSD of 1.5 % over 30 days), and high anti-interference performance against structural sulfonamide analogues and common environmental contaminants. When applied to spiked environmental water samples, the method achieved a recovery rate of 95.2–106 %, demonstrating its feasibility for on-site antibiotic residue detection.