In-tube solid phase extraction with graphitic-based polyurethane sponge as a superhydrophobic sorbent and determination of drug residues in foodstuffs using high-performance liquid chromatography

•Functonalization of polyurethane sponge with graphitic materials.•Development of In-tube SPE method.•Extraction of drug residues from food samples.•HPLC method development for the determination of drug residues. Veterinary drugs used in animal husbandry raise public health concerns due to their residues in the bodies of animals. This study employs a simple and quick sample preparation technique, in-tube solid phase extraction, to extract drug residues from foodstuffs, including eggs, honey, and water. This technique utilizes the synergy of graphitic-based materials and polyurethane sponges (PU) combined through dip coating method to make reusable sorbents for extracting drugs, including amoxicillin, paracetamol, ciprofloxacin, and cefixime. These prepared sorbents were characterized using FTIR, SEM, and XRD. HPLC analysis assessed the extraction efficiency, considering various parameters such as analyte concentration, sample solution pH, extraction time, type of eluting solvent, and graphitic-based polyurethane sponge reusability and stability. The proposed method exhibited a linear response for all three sorbents in the range of 0.03–1000 µg mL−1, with LOD 0.03–1.60 µg mL−1 and LOQ 0.18–4.84 µg mL−1. The % RSD ranged from 1.3 to 9.3 %, with recoveries of up to 98.42 %.