Carrier mediated hollow fiber liquid phase microextraction combined with HPLC-UV for preconcentration and determination of some tetracycline antibiotics.

A novel method of analysis for the trace residue determination of tetracyclines in animal tissues and fluids has been developed. Clean‐up of sample extracts is based upon the specific ability of tetracyclines to chelate with divalent metal ions (metal chelate affinity chromatography, MCAC) and determination made by high‐performance liquid chromatography. The method has been tested for the determination of oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) in porcine kidney and muscle, ovine kidney, bovine kidney and milk, and trout muscle. Recoveries at the 0.05 mg/kg level for OTC, TC and CTC respectively were 75%, 63%, 73% in porcine kidney, 77%, 79%, 76% in porcine muscle, 85%, 54%, 53% in bovine kidney, 78%, 63%, 57% in ovine kidney, 75%, 58%, 56% in fish (trout) muscle, and 80%, 59%, 59% in bovine milk. At this level both within‐ and between‐batch precision, as measured by the coefficient of variation (CV), was less than 10%. Determination to the 0.01 mg/kg level was carried out in ...

Analysis of trace residues of tetracyclines in animal tissues and fluids using metal chelate affinity chromatography/HPLC.

A sensitive microbiological detection system for tetracyclines, utilizing an Escherichia coli strain containing a cloned tetA-lacZ gene fusion, is described. Expression of beta-galactosidase by the fusion plasmid pUB3610 remained subject to regulatory control by the TetR repressor protein, with the presence of tetracyclines in the growth medium leading to a 12-fold induction of beta-galactosidase synthesis. Because synthesis of beta-galactosidase was influenced to a small extent by the carbon source and the addition of cyclic AMP to the medium, cells were grown in the presence of cyclic AMP to enhance the sensitivity of the assay. All commonly marketed tetracyclines and some derivatives at concentrations as low as 0.1 ng/ml could be detected in the growth medium. A plate assay utilizing the fusion plasmid that detects 1 ng of tetracycline has also been developed.

Sensitive biological detection method for tetracyclines using a tetA-lacZ fusion system.

Simple continuous and simultaneous determination of tetracycline residues

Description d'une technique de dosage de cet antibiotique et comparaison avec les resultats obtenus par la methode AOAC de chromatographie sur plaque cylindrique

Lori L Rhodig

Papers

Liquid Chromatographic Determination of Chlortetracycline in Premixes