Flow injection chemiluminescence determination of isoxicam based on diperiodatoargentate(III)-fluorescein system in a micellar medium

A novel and highly sensitive flow injection chemiluminescence (FI-CL) method has been developed for the assay of isoxicam. The method is based on the luminescence of the diperiodatoargentate(III)-fluorescein-isoxicam system, where fluorescein is used as an energy-transfer reagent in alkaline medium. The emission intensity is greatly enhanced by the presence of cetyltrimethylammonium bromide (CTAB). Optimum conditions and possible mechanisms have been investigated. The relative CL intensity is linear with the isoxicam concentration in the range of 3.0×10−10–1.0×10−6 g/ml with a detection limit of 7.0×10−11 g/ml (3σ). The relative standard deviation (RSD) is 1.7% at 1.0×10−8 g/ml of isoxicam (n=11). The present CL procedure was successfully applied to the determination of isoxicam in pharmaceutical formulations and biological fluids.