Matrix solid-phase dispersion combined with thin-layer chromatography-direct bioautography for determination of enrofloxacin and ciprofloxacin residues in milk

Enrofloxacin is a common veterinary antibiotic, which can be found as a residue in milk, together with its main metabolite, ciprofloxacin. Chromosorb WAW was used as a sorbent for matrix solid-phase dispersion of milk samples spiked with these antibiotics. This pre-separation method was combined with thin-layer chromatography-direct bioautography to obtain semi-quantitative results. Various modes of the procedure were tested and the one giving the best recovery of the antibiotics from milk was chosen.