ABSTRACT
In the presence of ZnO nanoparticles ( ZnO NPs ) and EDTA, luminol could produce strong chemiluminescence ( CL) without any oxidant. Therefore, a new CL system was established based on luminol-EDTA-ZnO NPs. As caffeic acid could strongly inhibit the CL, a flow injection CL method for the determination of caffeic acid was proposed. Under the optimized conditions, the relative CL intensity was linear over the logarithm of concentration of caffeic acid ranging from 1 . 0í10-7 mol/L to 1 . 0í10-5 mol/L with the detection limit of 1. 8í10-8 mol/L (3σ). The relative standard deviation (RSD) for the determination of 4 . 0í10-7 mol/L caffeic acid was 3 . 5% ( n=11 ) . The new method was successfully applied to determine the caffeic acid content in the tablets with the recoveries in the range of 97%-101%.