Objective To establish a quantitative analysis method to determine the content of the Sulfur dioxide (SO2) in Tianhuafen by ion chromatography-direct extraction. Methods The SO2 was extracted by potassium hydroxide solution(25 mmol/L) directly with AS11-HC chromatographic column(4 mm×250 mm,9.0μm);column temperature was 20℃;eluent was potassium hydroxide solution(20 mmol/L);the flow rate of eluent was 1.00 mL/min. Conductivity detection was adopted with the conductivity temperature of 20℃. The separating degree experiment,precision experiment and repetitive test were adopted to detect and calcu-late degree of separating,peak area of sulfite,content of SO2 in each gram of Tianhuafen and the relationship between peak area and sample volume. Results The chromatographic peak of sulfite had good separating degree with its adjacent chromatographic peak,and the peak area changed little;the mean content of sulfite was 0.197 7 mg in each gram of Tianhuafen with the RSD of 0.6%. When the injection quantity of sulfite sample was in the range of 1.16-29.1μg, which meant when the injection volume of sulfite was 100μL and the concentration range of solutions was within 11.6-291.2μg/mL,there was good linear relationship be-tween the injection quantity and peak area of sulfite. The average recovery rate was 99.2%,and the limit of quantification (LOQ) was 0.00 138μg/mL. Conclusion The method of ion chromatography-direct extraction is simple,accurate,rapid and appropriate for the quantification of SO2 in Tianhuafen.%目的：建立离子色谱直接提取法测定天花粉中二氧化硫（SO2）含量的实验方法。方法采用氢氧化钾溶液（25 mmol/L）直接提取，色谱柱为AS11-HC色谱柱（4 mm×250 mm，9.0μm）；柱温20℃；淋洗液：氢氧化钾溶液（20 mmol/L）；淋洗液流速1.00 mL/min；电导检测法，电导池温度20℃通过分离度实验、精密度实验、重复性实验检测并计算分离度、亚硫酸根峰面积和天花粉中SO2含量及亚硫酸根峰面积与进样量的关系。结果亚硫酸根色谱峰与其他相邻色谱峰间有较好的分离度，峰面积变化不大，亚硫酸根平均含量为每克天花粉含SO20.1977 mg、RSD为0.6%。亚硫酸根标准溶液进样量在1.16～29.1μg（即当进样体积为100μL时，被测定溶液浓度为11.6～291.2μg/mL）与亚硫酸根色谱峰的峰面积有良好的线性关系，平均回收率为99.2%，最低定量限以被测定溶液计算为0.00138μg/mL。结论离子色谱法操作简便、准确、快速，适用于天花粉中SO2的定量检测。
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