Application of the chemiluminescence system composed of silicon-doped carbon dots, iron(II) and K2S2O8 to the determination of norfloxacin

The authors describe a new chemiluminescence (CL) system composed of Si-doped carbon dots (Si-CDs), Fe(II) ions, and K2S2O8. The Si-CDs were prepared by a hydrothermal method and characterized by fluorescence spectra, transmission electron microscopy, energy-dispersive X-ray and FTIR spectroscopy. The weak CL of the Fe(II)-K2S2O8 reaction is found to be intensified by a factor of similar to 125 in the presence of Si-CDs. The possible mechanism for CL and its enhancement was studied by recording fluorescence and CL spectra and by investigating the effect of some radical scavengers. It is found that norfloxacin exerts a strong enhancing effect on the CL intensity of the system. This finding was employed to design a CL-based norfloxacin assay that works in the 5.0 to 300 mu g L-1 concentration range, with a limit of detection (3 sigma) of 1.5 mu g L-1. The method was applied to the determination of therapeutic levels of norfloxacin in spiked human plasma and gave satisfactory results.