Study on the method for detection of residual sulfur dioxide in Gastrodiae rhizoma

Objective To establish an ion chromatographic method for the determination of residual sulfur dioxide in Gastrodiae rhizoma.Methods Steam from samples distilled by 30 mL·L-1 hydrochloric acid solution,transfered by N2,was absorbed by 30 mL·L-1 hydrogen peroxide.The absorption liquid was analyzed by ion chromatography.A-SUPP5-150 anion analytical column was used with an eluent consisted of 3.2 mmol·L-1 Na2CO3 and 1.0 mmol·L-1 NaHCO3 solution.The velocity of flow rate was 0.7 mL·min-1.Results Linear range was 1.667 ~133.38 μg·mL-1(calculated by SO2),and the average recovery was 98.0%.Conclusion The method is easy to operate and shows good reproducibility and accuracy for the determination of residual sulfur dioxide in Gastrodiae rhizoma.