目的:建立紫花大叶柴胡柴胡皂苷a的含量测定方法。方法:色谱条件Phenomenex luna C18色谱柱(4.6 mm×250 mm,5μm),以甲醇-水(74∶26)为流动相,流速0.9 mL.min-1,柱温35℃,检测波长200 nm。结果:柴胡皂苷a进样量在0.11～4.4μg与峰面积线性关系良好(r=0.999 9)。柴胡皂苷a平均回收率为97.42%,RSD 1.42%。结论:紫花大叶柴胡中柴胡皂苷a的HPLC梯度洗脱法灵敏、准确,专属性强,重复性好。 Objective: To establish a method for determination of Radix Scutellariae saikosaponin a. METHODS: The chromatographic conditions Phenomenex luna C18 column (4.6 mm × 250 mm, 5 μm) was used. The mobile phase consisted of methanol and water (74:26) with a flow rate of 0.9 mL · min-1 and the column temperature was 35 ℃ with a detection wavelength of 200 nm. Results: The injection of saikosaponin a had a good linear relationship (r = 0.999 9) between 0.11 ~ 4.4μg and peak area. The average recoveries of saikosaponin a were 97.42% and RSD 1.42%. Conclusion: The gradient elution method of saikosaponin a from Radix Bupleurum is sensitive, accurate, specific and reproducible.