Flow injection-chemiluminescence determination of ascorbic acid based on luminol-ferricyanide-gold nanoparticles system

A novel flow-injection chemiluminescence (CL) method for the determination of ascorbic acid (AA) is proposed, based upon its enhancing effect on the CL reaction of luminol with ferricyanide catalyzed by gold nanoparticles in alkaline solution. Different sizes gold nanoparticles exhibited different catalyzing effect towards luminol CL and 38 nm gold nanoparticles exhibited the best enhancing effect. Under the optimal experimental conditions, a linear relationship was obtained between the CL intensity and the concentration of ascorbic acid in the range of 1.0×10−10-1.0×10−6 mol L−1. The detection limit was 2.0×10-11 mol −1 and the relative standard deviation for 1.0×10−6 mol L−1 ascorbic acid was 0.71% (n=10). This method has been successfully applied in the determination of ascorbic acid in several real samples.