Silver nanoparticle-based chemiluminescence enhancement for the determination of norfloxacin

A chemiluminescence (CL) method is presented for the flow injection determination of norfloxacin (NFLX). It is based on the fact that the weak CL of the Ce(IV)-Na₂SO₃ redox system is strongly enhanced in the presence of silver nanoparticles. UV-visible and fluorescence spectroscopy was carried out and showed that the energy of the intermediate SO₂*, originating from the reaction of Ce(IV) with Na₂SO₃, was transferred to Tb³⁺ via NFLX, and that the silver nanoparticles (AgNPs) accelerate the process due to the electric activity of AgNPs. Norfloxacin was detected by measuring the CL intensity which increases linearly with the concentration of NFLX in the range from 10 nM to 50 μM. The detection limit is lowered to 2.0 nM. The method was successfully applied to the determination of NFLX in eyedrops.