Chemiluminescent Determination of Ascorbic acid in Juices

Abstract A highly sensitive and rapid chemiluminescent assay method for ascorbic acid was developed. The stopped flow analysis method was applied to the measurement of ascorbate concentrations using 10 or 50 μM H2O2, 0.5 mM luminol and 4 U/ml peroxidase to induce the chemiluminescence. A suppression of the light emission occurred in less than 1 min, and the signal was linearly proportional to the ascorbate concentration from 0.1 to 16 μM, with a relative standard deviation of less than 2% over the measurable range (n=4). This suppression of light emission by ascorbate was completely returned to its original unimpeded level of light emission by stopping the flow for several seconds, while suppression by sulfite was not reversible. The method has proven to be good for ascorbate analysis in various juices and wines.