Determination of quinolones residues in prawn using high-performance liquid chromatography with Ce(IV)–Ru(bpy)32+–HNO3 chemiluminescence detection

A novel method was developed for the determination of quinolone (QN) residues such as ofloxacin, norfloxacin, ciprofloxacin and lomefloxacin by high-performance liquid chromatography (HPLC) coupled with chemiluminescence (CL) detection. The procedure was based on the chemiluminescent enhancement by QNs of the Ce(SO4)2–Ru(bpy)32+–HNO3 system. The separation was carried out with an isocratic elution using the mobile phase of 3:15:82 (v/v/v) acetonitrile–methanol–ammonium acetate buffer (containing 7.5 × 10−4 M TBAB, 0.8% (v/v) TEA and 1.0 × 10−4 M ammonium acetate, pH 3.65) at a flow rate of 1.0 ml/min. For the four QNs, the detection limits at a signal-to-noise of 3 ranged from 0.36 to 2.4 ng/ml. The relative standard deviations for the determination of QNs ranged from 1.6 to 4.5% within a day (n = 11) and from 3.7 to 6.2% in three days (n = 15), respectively. The method was successfully applied to the determination of QNs in prawn samples. The possible mechanism of the CL reaction was also discussed briefly.