Thin-layer chromatography-direct bioautography of flumequine residues in milk

Fluoroquinolone antibiotics are a relatively new group of synthetic antibiotics derived from 3-quinolone carboxylic acid. They are widely used in both human and veterinary medicine. Flumequine is frequently used in fish, poultry, and cattle husbandry for the treatment and prevention of diseases. It is also used to enhance weight gain of livestock as a feed or water additive. Hence, the antibiotic residues may be present in edible products, e.g., in meat, eggs, or milk. Thin-layer chromatography-direct bioautography combines TLC with microbiological detection. In the present paper, conditions for bioautographic detection of flumequine were determined for the antibiotic standards. The established method was applied for semi-quantitative determination of flumequine residues in milk. Matrix solid-phase dispersion was used as a pre-separation method.