RESUMO
A simple and rapid method for the determination of residues of enrofloxacin and its metabolite ciprofloxacin in edible tissues of farm animals using turbulent flow chromatography/tandem mass spectrometry (TFC-MS/MS) is described. The tissue samples were extracted with a mixture of acetonitrile, water and formic acid. After addition of internal standard solution, an aliquot of the extract was injected into the turbulent flow chromatography system. Matrix components contained in the injected sample were separated from the retained analytes on a polymer-based extraction column suited for pretreatment of samples at high flow rates. The analytes were eluted to an analytical column and the quantitative determination was performed using a tandem mass spectrometric detector. The run time for the analysis was 4 min. The limit of quantitation (LOQ) was 25 microgkg(-1) for each analyte and tissue material. Validation was performed in edible tissues of cattle, pig, turkey and rabbit in the range from 25 microgkg(-1) to at least twice the MRL. Mean recovery rates for the tissues of the different species were in the range from 72 to 105% with a coefficient of variation (CV) between 4.3 and 18%.