Indirect Determination of Ascorbic Acid by Atomic Absorption Spectroscopy

A new and simple method followed by atomic absorption spectrometry has been developed for indirect determination of ascorbic acid (AA). The proposed method was based on the oxidation of AA to dehydroascorbic acid with Cu2+cation(200mgL-1)in an ammonium thiocyanatesolution at pH2.4. AA reduces Cu2+to Cu+followed by the precipitation of Cu+ with SCN-. Then, the excess of Cu2+in the solution was measured by the atomic absorption spectrometry.The results showed that AA can be sensitively measured in the linear range of 2.0 to 40.0 mgL-1 with the detection limit of 1.5mgL-1.The relative standard deviation (%RSD) was 0.319 in 7 determination of 2.0 mgL-1 AA. Finally, the method was successfully used for the determination of AA in tablets containing various amounts of AA.