[Determination of sulphur dioxide in commonly used Chinese herbal medicines with both food and medicine function for health care by ion-chromatographic method].

OBJECTIVE: To dertermine SO2 in Chinese herbal medicine with both food and medicinal functions. METHODS: A distilling and ion-chromatorgraphic method was applied. RESULTS: The results indicated that among 32 commonly used Chinese herbal medicines, 26 samples contained sulphur dioxide, varying in its contents and up to 3180 microg/g. The amount of sulphur dioxide did not change much after samples were washed by water. On the other hand, sulphur dioxide contents decreased after samples were exposed outdoor or boiled in water. CONCLUSION: The method was simple, accurate and reproducible.