A novel silica aerogel sponge/melamine formaldehyde prepolymer composite sorbent for the detection of tetracycline antibiotics in aquatic environments: sorbent preparation and performance evaluation

Antibiotic pollution, particularly the overuse of tetracycline antibiotics (TCs), poses a significant threat to aquatic environments. Solid-phase extraction (SPE) is widely used for water sample pretreatment, and developing cost-effective, easily synthesized packing materials remains an active area of research. In this study, a novel filler material (SAS-MFP) was developed by combining commercial melamine-formaldehyde prepolymer (MFP) with a silica aerogel sponge (SAS), offering excellent water permeability, simple fabrication, and low cost. Characterization results revealed that the two materials were well integrated, with MFP evenly distributed across the surface of the silica aerogel. The adsorption mechanism of SAS-MFP was investigated through adsorption experiments. The results fit the Langmuir isotherm and pseudo-second-order kinetic models, indicating that SAS-MFP primarily adsorbs via chemisorption. Optimized SPE conditions led to the highest recovery (97.6 %) for four TCs under pH 7, using 400 mg of sorbent, a flow rate of 120 s·mL −1 , 5 % acetonitrile as the rinsing solvent, and 5 mL of 1 M oxalic acid–acetonitrile (1,4, v v −1 ) as the eluent. Furthermore, the limit of detection for TCs in blank water samples ranged from 0.09 to 0.12 μg·L −1 , with inter-day and intra-day relative standard deviations ranging from 2.46 % to 7.38 % and 4.58 % to 9.31 %, respectively, demonstrating the method's sensitivity and reproducibility for practical applications.