Determination of chlortetracycline in swine plasma by LC-ESI/MS/MS

A rapid, selective and sensitive method has been developed for the determination of chlortetracycline in swine plasma by LC-ESI/MS/MS. The method consists of a protein precipitation extraction for sample preparation and liquid chromatography ionspray tandem mass spectrometry for analysis. The plasma samples were extracted with acetonitrile and the supernatants were analyzed using an LC-ESI/MS/MS instrument. Separation was achieved using a C(8) analytical column and an isocratic mobile phase composed of 70:30 acetonitrile:0.5% formic acid in water at a flow rate of 500 microL/min. A linear (weighted 1/concentration) relationship was used to perform the calibration over an analytical range 20--2000 ppb (ng/mL). The intra-batch precision and accuracy at LLOQ, medium and high concentrations were 9.0, 11.3 and 9.9% and 97.7, 100.3 and 98.4%, respectively, and the inter-batch precision and accuracy at LLOQ, medium and high concentrations were 9.1, 8.4 and 7.4% and 95.1, 102.1 and 97.1%, respectively. This LC-ESI/MS/MS method for the determination of chlortetracycline in swine plasma has been proven to be within generally accepted criteria used for bioanalytical assay.