Development of a gallate-based metal-organic framework/activated carbon composite for the pipette-tip solid phase extraction, and HPLC-UV determination of sulfonamides from milk, egg, and honey

A novel pipette tip solid-phase extraction (PT-SPE) method was developed using copper-gallic acid metal organic framework/Activated carbon (Cu-GA MOF/AC) composite as an adsorbent for the extraction of sulfonamide residues from food products. The composite was prepared utilizing an in-situ growth approach and analyzed using FTIR, XRD, and SEM. Compared to AC, the Cu-GA MOF/AC composite exhibited a high surface area, structural stability leading to improved adsorption capacity. The extraction conditions, including sorbent amount, pH, elution solvent, and volume, were optimized to achieve maximum extraction recovery. The optimized PT-SPE method was combined with HPLC-UV for determination of sulfonamides in milk, egg, and honey samples. The composite based method demonstrated superior analytical performance with better linearity, lower detection limits (0.03-0.35µgmL-1), and higher recoveries (up to 99.29%) as compared to AC. Moreover, the composite retained its extraction efficiency over six extraction cycles, whereas AC showed a progressive decrease in performance.