Identification of antibiotic residues in milk by thin-layer chromatography

A scheme has been devised that makes it possible to separate and identify, by means of thin-layer chromatography, the 14 different antibiotic resudues in milk which are, besides penicillin, the most widely used in mastitis control: cloxacillin, dihydrostreptomycin, tetracycline, oxytetracycline, chlortetracycline, chloramphenicol, neomycin, novobiocin, bacitracin, erythromycin, oleandomycin, ampicillin, streptomycin and oxacillin. The limits of detectability of the antibiotics studied vary between 0.1 and 3 mug/ml, with the exception of neomycin the minimum detectable concentration of which is 15 mug/ml.