RESUMO
Objective:To determine residual sulfite in traditional Chinese medicinal materials or pieces processed by sulfur fumi-gation respectively by iodine titration, acid-base titration and ion chromatography and compare the results. Methods:The three meth-ods were used to determine four kinds of Chinese herbal medicines including Codonopsis radix, Dioscoreae rhizoma, Achyranthis bident-atae Radix and Atractulodis Macrocephalae Rhizoma, the recovery tests were also performed and the results were analyzed and compared to summarize the characteristics and quality control requirements of each method. Results:Iodine titration and acid-base titration had the advantages of simple operation process and low cost. However, there were many interference factors in the two methods, and due to different principles, they were suitable for the determination of different varieties of herbal medicines. Ion chromatography method had the advantages of high sensitivity and strong specificity, while the cost was high. Conclusion: It is suggested that proper methods should be chosen for the determination of sulfur dioxide residues according to actual situations.