目的 建立高效液相色谱-串联质谱法（LC-MS/MS）测定人血浆中氯法拉滨浓度。方法 采用API3000串联质谱仪及Shimadzu系列液相色谱仪进行检测。血浆样品经乙酸乙酯提取处理，以克拉屈滨为内标。色谱柱为Thermo C₁₈柱（4.6 mm×150 mm，5 μm），流动相为乙腈-水（250∶3，其中含4 mmol的乙酸铵和0.3%的甲酸），流速为0.5 mL·min^-1。氯法拉滨和克拉屈滨的MRM扫描离子通道m/z分别为304.0→170.0，286.1→170.0。进样体积为20 μL，每个样品的分析时间为5 min。结果 氯法拉滨和克拉屈滨保留时间分别为4.00，4.11 min。氯法拉滨在10~2 000 ng·mL^-1内线性关系良好（r=0.999 5），日内、日间RSD均低于9.60%，准确度为101.10%~102.94%。结论 本法样品预处理简便快速，检测准确、灵敏、专一，适用于氯法拉滨药动学的研究。

OBJECTIVE To establish a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of clofarabine in human plasma. METHODS The drug was determinated by LC-MS/MS using electrospray ionization. The plasma samples were extracted with ethyl acetate. Cladribine was the internal standard (IS). The analytical column was Thermo C₁₈ column (4.6 mm×150 mm，5 μm). The mobile phase consisted of acetonitrile-water (250∶3，Which contains 4 mmol of ammonium acetate and 0.3% formic acid) at a flow rate of 0.5 mL·min^-1. Clofarabine and cladribine were detected on multiple reaction monitoring (MRM) by the transitions from the precursor to the product ion (m/z 304.0/170.0 and m/z 286.1/170.0). The injection volume was 20 μL and the total run time was 5.0 min. RESULTS Calibration curve showed good linearity in the range of 10-2 000 ng·mL^-1 (r=0.999 5). The intra-batch and inter-batch precisions (RSD) were all less than 9.60% and the accuracy was within 101.10%-102.94%. CONCLUSION The retention time of cladribine and clofarabine were 4.00 and 4.11 min. The established LC-MS/MS method is sensitive，accurate and simple for the determination of clofarabine in human plasma. It is suitable for the pharmacokinetics of clofarabine.