Flow–injection chemiluminescence determination of ascorbic acid by use of the cerium(IV)–Rhodamine B system Original Research Article

A highly sensitive flow–injection (FI) method with chemiluminescence (CL) detection is used for the determination of l-ascorbic acid. The method is based on the CL reaction of Rhodamine B with cerium(IV) in sulfuric acid media. l-Ascorbic acid is suggested to be a catalyst utilized in the energy-transferred excitation process. The proposed procedure allows quantitation of l-ascorbic acid in the range 3.8×10−13 to 1.0×10−10 mol l−1 with a correlation coefficient of 0.9998 (n=5) and relative standard deviation (R.S.D.) of 0.92% (n=11) at 1.0×10−11 mol l−1. The detection limit (3×blank) was 1.0×10−13 mol l−1. The method is successfully used to determine l-ascorbic acid in fresh vegetables. The possible mechanism of the chemiluminescence in the system is discussed.