Design of acid-regulated zirconium-based MOFs for efficient enrichment and sensitive detection of sulfonamide antibiotics.

Sulfonamide antibiotics (SAs) are widely used broad-spectrum antibacterials whose residues raise serious food safety concerns. Efficient enrichment of trace SAs requires advanced sorbents. Herein, we report that acid-modulated defect engineering in Zr-MOFs (MOF-525-X) significantly enhances their enrichment and detection performance for SAs. Of these, MOF-525-6 exhibited optimal performance, combining rapid kinetics, high capacity (225.07-1173.22 mg g-1), and high enrichment factors (228-446), which collectively surpass most reported SAs sorbents. DFT calculations identified non-covalent interactions as the primary driving force between the sorbent and SAs. Furthermore, a dispersive solid-phase extraction coupling with HPLC-DAD was established, and the method exhibited a wide linear range (0.1-500 ng·mL-1) and low detection limits (0.03-0.13 ng·mL-1). Subsequently, MOF-525-6 was effectively applied to extract trace SAs from chicken, eggs, and milk, achieving high recovery (83.55-109.73 %) and precision (1.73-9.55 %). This work not only provides an efficient sorbent for SAs monitoring but also offers valuable insights into defect-based functional design of MOFs.