EN
An effective liquid chromatographic method with tandem mass spectrometric (LC-MS/MS) detection and identification was developed for the determination of thiamphenicol and florphenicol in the chicken liver and kidneys. After a preliminary dissolution in ethyl acetate and a homogenisation step, the obtained extract was evaporated to dryness and dissolved in water. The solution was clean up on an octadecyl (C18) solid phase extraction (SPE) cartridge. LC-MS/MS, electrospray ionisation in the negative ion mode was used for determination of the compounds followed by separation on the octadecyl column. The whole procedure was validated according to the requiments of Commission Decision 2002/657/EC and the samples were spiked with thiamphenicol and florphenicol at the levels of 50-75-100-500 µg kg⁻¹. At these levels, recovery ranged between 95.0% and 103.0%, and the within-laboratory reproducibility was lower than 5.03%. The limit of decision (CCα) for thiamphenicol and florphenicol in the kidneys were established at the level of 55.3 µg kg⁻¹ and 54.4 µg kg⁻¹, respectively, and in the liver at the level of 55.3 µg kg⁻¹ and 54.7 µg kg⁻¹. The results of the validation demonstrated that this method meets criteria for determination and confirmation of thiamphenicol and florfenicol in biological material.