Inert matrix and Na4EDTA improve the supercritical fluid extraction efficiency of fluoroquinolones for HPLC determination in pig tissues

A supercritical fluid extraction method combined with high-performance liquid chromatography-fluorescence detection was developed for the determination of enrofloxacin, danofloxacin, and ciprofloxacin in pig muscle, lung, and kidney samples. The optimal SFE conditions were 80 °C, 300 kg/cm2, 30% methanol for 40 min as a dynamic extraction time, in addition to 0.2 g Na4EDTA and 7.0 g sea sand in the extraction vessel. The use of Na4EDTA and sea sand on SFE extraction resulted in improvement of the recoveries of ciprofloxacin, a polar and hydrophilic compound, as well as enrofloxacin and danofloxacin. Overall, the recoveries ranged from 86.7 to 113.1% using the Na4EDTA/sea sand-assisted SFE extraction method. The Na4EDTA/sea sand-assisted SFE-HPLC-FLD validated method was successfully carried out in pig tissues, and proved to be specific, sensitive, reliable, and accurate. The method was also applied satisfactorily for accurate quantitative residue analysis in incurred pig tissues.