Determination of Gallic Acid by Flow Injection Analysis Based on LuminoI-AgNO3-Ag NPs Chemiluminescence System

A novel flow injection procedure has been developed for the determination of gallic acid based on the en- hancement function for luminol-AgNO3-Ag NPs chemiluminescence （CL） system by gallic acid. The enhancement mechanism was proposed for the reinforcing effect of the gallic acid on the CL system. The UV-vis absorption spectrum and CL emission spectrum were applied to confirm the mechanism. The method is simple, rapid and sen- sitive with a detection limit of 5 × 10^-10 g.mL-l and a linear range of 8.0 × 10^-10- 1.0 × 10-7 g.mL-1. The relative standard deviation （RSD） is 1.3% for eleven measurements of 5 × 10^-8 g-mL-1 gallic acid. The method has been successfully applied to the determination of gallic acid in Chinese proprietary medicine--Jianmin Yanhou tablets and synthesized samples.