ANALYSIS OF QUINOLONIC ANTIBIOTICS BY HPTLC - OXOLINIC ACID RESIDUE ANALYSIS IN FISH TISSUE

Instrumental thin layer chromatography has shown to be a good choice o f method for the analysis of quinolone antibiotics, a group of antibio tics with therapeutic and prophylactic properties which have recently become extensively used in fish farming. A method for qualitative and quantitative analysis of these antibacterial compounds is proposed. Th e method is suitable for quality control analysis of antibiotic added to fish feed and also for detection and quantification of residues in fish meat. Samples were extracted with a 70:30 (nu/nu) mixture of acet onitrile and an aqueous solution of potassium chloride and potassium h ydroxide and, for fish meat, ultrasonic treatment. Clean-up procedures are also described. Nalidixic acid was used as internal standard. Rec overy efficiency from fish feed is over 97 % with coefficients of vari ation between 1 and 2 %. For analysis of oxolinic acid residues in fis h tissue, the plate is treated post-chromatography with sulfuric acid - hydrochloric acid reagent and scanned in fluorescence mode. This res ults in 10 ppb sensitivity.