Solid-phase extraction and TLC quantification of enrofloxacin, oxytetracycline, and trimethoprim in wastewater

Quantitative determination of the antibiotics enrolloxacin, oxytetracycline, and trimethoprim in aquatic samples is reported. The method involves solid-phase extraction (SPE) and preconcentration of the antibiotics, separation by thin-layer chromatography (TLC) and quantification by video densitometry. TLC separation was performed on HPTLC CN F(254)s plates with H2C2O4-methanol as mobile phase. Spots were detected and quantified at X = 254 nm by videodensitometry. Limits of detection (LOD) and limits of quantification (LOQ) for TLC determination were calculated. The method was evaluated for spiked water samples. Antibiotics were extracted by solid-phase extraction (SPE) on a polystyrene-divinylbenzene (SDB) Empore extraction disk. The extraction efficiency was checked by recovery experiments.