Investigation on sensitized chemiluminescence systems and their mechanism for five fluoroquinolones.

The novel chemiluminescence (CL) reaction systems were established for lomefloxacin (LMFX), ofloxacin(OFLX), norfloxacin (NFLX), gatifloxacin (GAFX) and enoxacin (ENX). The sensitized CL emission mechanism was investigated for the five systems by comparing the fluorescence emission with CL spectra. For LMFX-Ce(IV)-S2O3(2-)-H2SO4 and OFLX-Ce(IV)-S2O4(2-)-H2SO4 systems, the CL intensity is enhanced through intermolecular energy transfer from the excited SO2* to LMFX and OFLX. For NFLX-Ce(IV)-S2O4(2-)-HNO3 system, the sensitized CL is based on intermolecular energy transfer from the excited SO2* to NFLX oxide. For Eu3+-GAFX-Ce(IV)-S2O4(2-)-HCl and Dy3+-ENX-Ce(IV)-S2O3(2-)-H2SO4 systems, the CL spectra are from the narrow characteristic emission at 590, 619 and 649 nm of Eu3+* (5D0-->7F1, 5D0-->7F2, 5D0-->7F3) and at 482 and 578 nm of Dy3+ (4F9-->6H15/2, 4F9-->6H13/2) through intermolecular energy transfer from the excited SO2* to GAFX and ENX, followed by intramolecular energy transfer from GAFX* to Eu3+ and ENX* to Dy3+. The conditions of CL emission were investigated and optimized. The proposed five enhanced CL systems have good linearity, higher sensitivity, precision and potential capability for residue analysis of studied analytes in foods and biological samples.