Simultaneous Determination of Flumequine and Oxolinic Acid Residues in Aquatic Products Using Pressurized Capillary Electrochromatography

A rapid method for detection of flumequine (FQ) and oxolinic acid (OA) residues from fish tissues was established using pressurized capillary electrochromatography (pCEC). Residual FQ and OA were extracted from fish tissue samples with acidified acetonitrile and purified on an Oasis HLB C18 solid-phase extraction column. The extract was then analyzed by pCEC with the mobile phase (pH = 3) consisting of acetonitrile and 15 mM ammonium acetate (45: 55, v/v, respectively) at the flow rate of 0.07 mL/min, detection wavelength of 324 nm, and applied voltage of −10 kV. Baseline separation of FQ and OA was achieved in 10 min; both drugs showed good linearity in the range of 0.2–5 μg/mL. The recoveries of FQ and OA were between 82 and 92 % (relative standard deviation = 3.63–5.96). The limits of detection for FQ and OA were 0.1 and 0.08 mg/kg, respectively.