Dysprosium-sensitized chemiluminescence reactions: Their mechanism and application to the determination of synthetic quinolone antibiotics

Dysprosium-sensitized chemiluminescence (CL) reactions have been suggested for the determination of enoxacin (ENX), fleroxacin (FLX), pefloxacin (PFX) and pipemidic acid (PPA). The CL conditions of Dy⁺³-ENX-MnO₄⁻-S₂O₃⁻²-HNO₃, Dy⁺³-FLX-MnO₄⁻-S₂O₃⁻²-H₆P₄O₁₃, Dy⁺³-PFX-MnO₄⁻-S₂O₃⁻²-HCl, and Dy⁺³-PPA-MnO₄⁻-S₂O₃⁻²-H₂SO₄ systems were investigated and optimized. The CL spectra are formed from the narrow characteristic emission of Dy⁺³ at 482 and 578 nm through the intermolecular energy transfer from the excited SO₂^* to analyte, followed by intramolecular energy transfer from analyte* to Dy⁺³. The calibration curves for the four analytes have good linearity. The relative standard deviations (RSDs) are in the range of 1.6–1.9% for 11 determinations of 6.0 × 10⁻⁸ g/mL of ENX, FLX, PFX, and PPA. The detection limits (3σ) are in the range of 2.2 × 10⁻¹⁰–6.0 × 10⁻¹⁰ g/mL. The proposed four CL-based methods have high sensitivity, precision and potential capability for the determination of residues of quinolone synthetic antibiotics in foods and biological samples.