目的 建立超快速液相色谱-质谱/质谱联用（UFLC-MS/MS）法测定酚酞片中酚酞的量。方法 样品以乙醇提取、微孔滤膜滤过、离心后，通过电喷雾离子化（ESI），采用多反应检测（MRM）方式进行正离子检测，用于定量分析的检测离子为m/z 319.0→225.2。采用Shim-pack XR-ODS色谱柱（75 mm×3.0 mm，2.0 μm）分离，以乙腈-水-甲酸（55∶45∶0.1）为流动相，体积流量为0.40 mL/min，在3 min内完成酚酞定量分析。结果 线性范围为2.5～1 000.0 ng/mL，最低检测限为2.5 ng/mL；日内RSD小于1.85%，日间RSD小于2.56%。结论 本方法灵敏度高，分析速度快，操作简单，可作为酚酞片中酚酞质量控制方法。

Objective To establish an ultra fast liquid chromatography/tandem mass spectrometric (HPLC-MS/MS) method for the determination of phenolphthalein in Phenolphthalein Tablet (PT). Methods The samples were extracted by ethanol, filtered with microporous membrane, and centrifugated. LC/MS/MS detection was performed by using a triple-stage quadrupole mass spectrometer working in multiple reaction monitoring mode (MRM) with positive electrospray ionization (ESI), using the transitions of m/z 319.0→225.2 of phenolphthalein. Chromatographic separation was achieved using Shim-pack XR-ODS column (75 mm × 3.0 mm, 2.0 μm) with isocratic flow and elution with acetonitrile-water-formic acid (55:45:0.1) and a flow rate of 0.4 mL/min. The analyte was quantified in a single run within 3 min. Results The linearity was demonstrated over the expected concentration range of 2.5— 1 000.0 ng/mL, and the lower limit of quantification (LLOQ) was 2.5 ng/mL. The intra-day precision expressed as RSD was 1.85% or less, while the inter-day result was 2.56% or less for phenolphthalein. Conclusion The method is more convenient with good repeatabilityand high sensitivity, and could be successfully applied for the determination of phenolphthalein in PT.