Abstract: An ion chromatographic method using cerium(Ⅳ) postcolumn reaction and cerium(Ⅲ) fluorescence detection was employed to separate the anions of L-ascorbic acid, nitrite, sulfite, oxalate, thiosulfate and iodide in their mixtures. Some conditions for separating and determining above six species have been established. Using a 3×10^-3 mol/L carbonate eluent, these anions could by separated completely. The effects of the concentrations of cerium(Ⅳ) and sulfuric acid in the postcolumn reaction solution and the flow rate of the postcolumn reaction solution on the chromatographic peak-height were also tested.