A multi-functional effervescent tablet for one-pot effervescent/derivatization/extraction: An integrated strategy for...

Sulfonamides are extensively used antimicrobials, but residues in food raise health risks such as allergies, antimicrobial resistance, and carcinogenicity. Strict residue limits require sensitive and efficient monitoring methods. While LC-FLD is selective and practical, conventional workflows rely on multi-step extraction and derivatization, which are time-consuming. A streamlined strategy integrating extraction and derivatization into a single operation is needed for practical residue analysis in complex food matrices.

A novel multi-functional effervescent tablet was developed to unify effervescence, derivatization, and extraction in one step. The tablet incorporates effervescent precursors (Na₂CO₃/NaH₂PO₄), fluorescamine (a derivatization reagent), Fe₃O₄ nanoparticles, and hydroxylated multi-walled carbon nanotubes (an adsorbent). Upon immersion, CO₂ bubbles promote rapid dispersion of reagents and in-situ assembly of a magnetic composite adsorbent, enabling simultaneous derivatization and efficient extraction of sulfonamides. The core tablet-mediated procedure requires only 4 min, with desorption achieved in 0.5 min using acetone. Validation demonstrated excellent linearity (R² > 0.998), low detection limits (0.130-0.285 ng/g), and recoveries of 82.6-107.0% with RSDs <10%. Application to spiked honey confirmed accuracy, with relative errors ranging from -8.9% to +9.2%. Comparative studies showed performance equivalent to conventional multi-step protocols, while reducing handling steps and solvent use during the extraction phase.

This integrated effervescence/derivatization/extraction strategy streamlines sulfonamide residue analysis into a rapid, cost-effective, and easily automatable workflow. While sample pretreatment is still required for complex matrices, the tablet-based step significantly reduces manual handling and solvent consumption during the extraction and derivatization process. Its compatibility with LC-FLD provides a practical and cost-effective alternative to LC-MS, supporting reliable food safety surveillance within regulatory standards.