Extraction of Penicillin G From Dairy Products Using Deep Eutectic Solvent/Alginate Beads Enhanced via Layered Double Hydroxides

A new nanocomposite based on alginate microbeads impregnated with novel strontium–aluminum layered double hydroxide (Sr-Al LDH) incorporated with choline chloride-urea deep eutectic solvent (ChCl-U DES) was introduced. The microbeads and LDH were characterized by adsorption/desorption isotherms, Fourier-transform infrared spectroscopy, SEM, and x-ray diffraction. The adsorbent was employed for determining penicillin G (PENG) using dispersive solid-phase extraction prior to HPLC analysis. The extraction efficiency of the adsorbent, compared with that of unmodified alginate, showed a 2.5-fold increase. Significant parameters, including elution conditions, sorbent composition and mass, adsorption time, and sample pH, were optimized. The LOD was 0.4 µg kg⁻¹, and the linear range was 1.4–500 µg kg⁻¹. The LOQ (1.4 µg kg⁻¹) was lower than the established maximum level for PENG by the European Union (4 µg kg⁻¹). Enrichment factor and synthesis reproducibility were also investigated. The method's accuracy was evaluated through PENG analysis in dairy products and water, with recoveries of 81%–107% (RSDs < 7.6%). The procedure's greenness was assessed using the Analytical Eco-scale and achieved excellent green credentials. To the best of our knowledge, this is the first report on the synthesis and application of a novel alginate composite for the extraction of PENG from dairy and water samples.