Oxidation of certain fluoroquinolones using the chemical sources of reactive oxygen species in the presence of Tb(III) ions and analytical application of these systems

Abstract

Chemiluminescence (CL) generated in the process of oxidation of fluoroquinolones (FQ) in the reaction systems Fe(II)/(III)-H2O2 and KNO2-H2O2 in acidic environment, as the sources of reactive oxygen species, was studied. For all studied systems containing FQ (levofloxacin or enrofloxacin or pefloxacin) the kinetic curves of chemiluminescence decay were recorded and the emission obtained was subjected to spectral and kinetic analyses. Terbium(III) ions were used as sensitizers. A linear relation was found between the integral intensity of chemiluminescence (the area under the CL kinetic curve) and FQ concentration. The limits of detection for enrofloxacin, pefloxacin and levofloxacin were calculated to be 6 × 10−8 molL−1, 1.2 × 10−7 molL−1 and 9.4 × 10−7 molL−1, in the system FQ-Tb(III)-Fe(II)/(III)-H2O2 and 1.4 × 10−7 molL−1, 2.4 × 10−7 molL−1 and 1.4 × 10−6 molL−1, in the system FQ-Tb(III)-KNO2-H2O2. The recoveries were 96.7–102.5% for commercial formulations and urine samples and RSD was below 2.5%.