[Determination of sulfur dioxide in traditional Chinese medicine by alkaline solution extraction and ion chromatography].

Objective: An ion chromatographic method was developed to analyze sulfur dioxide in traditional Chinese medicine (TCM).

Method: The samples were extracted with alkaline solution and reacted with formaldehyde to form hydroxymethyl sulfonic acid. The extracts were cleaned by C18 column and SO3(2-) was determined with ion chromatography equipped with a conductance detector. In the method, AS11-HC chromatographic column was used and the mobile phase was 15 mmol x L(-1) KOH.

Result: The calibration curve was in good linearity in the range of 1 to 100 microg (r =0.9992). The detection limit was 0.53 mg x kg(-1) and the average recovery was 103.7%.

Conclusion: The method is simple, sensitive, precise, short-time-consuming, and the random error is smaller, which is applicable to the testing of large quantity batches of TCM.