GD-MOF/ACTIVATED CARBON COMPOSITE FOR SELECTIVE PIPETTE-TIP MICROEXTRACTION OF PENICILLIN AND CEPHALOSPORIN ANTIBIOTICS FROM MILK WITH UV–VISIBLE DETECTION
Keywords:
Gadolinium metal–organic framework, Activated carbon, Pipette-tip microextraction, Penicillin, Cephalosporin antibiotics, β-Lactam antibiotics, Milk analysis, UV–Visible spectrophotometry, Antibiotic residues, Food safety, Solid-phase extraction, Metal–organic framework composite.Abstract
Residues of β-lactam antibiotics, especially penicillin and cephalosporins, in milk are an important public health concern and require highly sensitive, quick, and eco-friendly analytical techniques for detection. A novel gadolinium-based metal–organic framework/activated carbon (Gd-MOF/AC) composite was prepared and used for selective sorption of penicillin and cephalosporin antibiotics for pipette-tip microextraction (PTME) of milk sample followed by their determination by UV–Visible spectrophotometry. The synthesized composite was analyzed by the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–Visible spectroscopy, and the results confirmed the formation of a porous hybrid material with abundant active adsorption sites. The synergic effect of Gd-MOF and activated carbon facilitated the adsorption by using hydrogen bonding, π–π interaction, electrostatic force, Lewis acid–base coordination and filling effect, which enables effective extraction of target antibiotics. The influence of solution pH, adsorbent dose and eluent volume on the extraction efficiency were studied systematically. The extraction performance was best at pH 6 with 100 mg of Gd-MOF/AC composite and 0.5 mL of eluent. The optimized conditions verified the high adsorption efficiency, the high selectivity, the good repeatability, and the acceptable analytical sensitivity of the proposed method for the determination of antibiotic residues in spiked milk samples, with minimal matrix interference. Developed PTME–UV–Visible method is an alternative method for routine monitoring of β-lactam antibiotic residue in dairy products, which is simple, fast, economical and environmentally friendly, compared to the traditional chromatographic technique. The outcomes underscore the great potential of Gd-MOF/AC composites as advanced sorbent materials in food safety analysis and residue monitoring in complex biological matrices.
