Simultaneous Determination of Six Tetracyclines in Bovine Tissue, Plasma and Urine by Reverse-Phase High-Performance...

A simple and rapid high-performance liquid chromatographic method was developed for the simultaneous separation and identification of six different tetracycline antibiotics (minocycline, oxytetracycline, tetracycline, dimethylchlortetracycline, chlortetracycline, and methacycline) in bovine kidney, plasma and urine. The antibiotics were separated at ambient temperature on a μ-Bondapak C₁₈ column using a mobile phase [water 760 ml, acetonitrile 240 ml, N,N'-dimethylfolmamine 60 ml, ethanolamine 5.0 ml and Na₂HPO₄ 5.2 g, pH 2.5] at a flow rate of 1.5 ml/min. A variable-wavelength detector set at 254 nm, 0.05 AUFS and a recorder set at 4mm/min were used for the detection. The entire mixture was resolved in less than 12 min by this method. The limits of detection for the tetracyclines ranged from 1.25 to 0.125 μg/ml. Recoveries of tetracyclines from biological samples were 72.3 - 80.6% kidney, 78.2 - 83.7% in plasma and 80.2 - 88.4% in urine, respectively. The method was sensitive, reproducible, and applicable to the quantitative analysis of tetracyclines in biological samples.