黄芩提取物样品中加入水，经甲醇超声提取2次，离心后，合并上清液，用水定容至50.0 mL，过0.22 μm微孔滤膜，采用超高效液相色谱-串联质谱法同时测定滤液中黄芩素、黄芩苷、汉黄芩苷、野黄芩苷等4种黄酮类成分的含量。以ACQUITY UPLC HSS T3色谱柱为固定相，以不同体积比的0.01%（质量分数）氨水和乙腈的混合液为流动相进行梯度洗脱，串联质谱分析中采用电喷雾离子源负离子模式（ESI^-）和多反应监测模式。4种黄酮类成分的质量浓度在5.0~500.0 μg·L^-1内与其对应的质谱响应值呈线性关系，检出限（3S/N）为0.3~1.5 μg·kg^-1，测定下限（10S/N）为1.0~5.0 μg·kg^-1。以空白黄芩提取物样品为基体进行加标回收试验，所得回收率为91.1%~99.1%，测定值的相对标准偏差（n=6）为2.0%~4.1%。

Water was added in the sample of Scutellaria baicalensis extract. The mixture was extracted twice with methanol ultrasonically. after centrifugation, the combined supernatant was made up to 50.0 mL with water. The solution was filtered on 0.22 μm microporous membrane. UHPLC-MS/MS was applied to the simultaneous determination of 4 flavonoids, i.e. baicalein,baicalin,oroxindin and scutellarin in the filtrate. ACQUITY UPLC HSS T3 chromatographic column was used as stationary phase, and the mixture of 0.01% (mass fraction) ammonia and acetonitrile mixed in different ratios was used as mobile phase in gradient elution. ESI^- and multi-reactions monitor mode were adopted in MS/MS. Linear relationships between response values of mass spectrometry and mass concentration of the 4 flavonoids were kept in the same range of 5.0-500.0 μg·L^-1, with detection limits (3S/N) in the range of 0.3-1.5 μg·kg^-1 and lower limits of determination (10S/N) in the range of 1.0-5.0 μg·kg^-1. On the base of blank sample of Scutellaria baicalensis extract, test for recovery was made by standard addition method; values of recovery found were in the range of 91.1%- 99.1%, with RSDs (n=6) of determined values in the range of 2.0%-4.1%.