High-performance liquid chromatographic determination of oxolinic acid and flumequine in the live fish feed artemia.

A high-performance liquid chromatography (HPLC) analytical method for the determination of oxolinic acid and flumequine in Artemia nauplii is described. The samples were extracted and cleaned up by a solid-phase extraction (SPE) procedure using SPE C18 cartridges. Oxolinic acid and flumequine were determined by reversed-phase HPLC using a mobile phase of methanol-0.1 M phosphate buffer, pH 3 (45:55, v/v) and a UV detection wavelength of 254 nm. Calibration curves were linear for oxolinic acid in the range of 0.2-50 microg/g (r2=0.9998) and for flumequine in the range of 0.3-50 microg/g (r2=0.9994). Mean recoveries amounted to 100.8% and 98.4% for oxolinic acid and flumequine, respectively. The quantification limit was 0.2 microg/g for oxolinic acid and 0.3 microg/g for flumequine. Quantitative data from an in vivo feeding study indicated excellent uptake of both drugs by Artemia nauplii.