LC-MS/MS法同时测定人血浆中对称性二甲基精氨酸和非对称性二甲基精氨酸的浓度

目的:建立快速、灵敏的方法同时测定人血浆中对称性二甲基精氨酸(SDMA)和非对称性二甲基精氨酸(ADMA)的浓度。方法:血浆样品经乙腈沉淀蛋白后,以高效液相色谱串联质谱电喷雾法进行测定,色谱柱为Thermo Hypercarb,流动相为乙腈∶甲酸铵-甲酸缓冲溶液(梯度洗脱),流速为0.40mL·min-1。采用电喷雾离子源(ESI源),以选择多反应监测(MRM)方式进行正离子检测,监测离子对分别是m/z203.1→172.1(SDMA)、m/z203.1→46.1(ADMA)和m/z272.2→171(右美沙芬)。结果:血浆中SDMA和ADMA的线性范围均为25～500ng·mL-1,定量下限均为25ng·mL-1。平均方法回收率均>97%,日内、日间RSD均<17%。结论:该方法专属性好,灵敏度高,准确快捷,适用于生物样品的快速检测。

Simultaneous Determination of Symmetric Dimethylarginine and Asymmetric Dimethylarginine in Human Plasma by LC-MS/MS

OBJECTIVE：To develop a sensitive and rapid method for simultaneous determination of symmetric dimethylarginine （SDMA） and asymmetric dimethylarginine （ADMA） in human plasma. METHODS： Plasma samples were extracted by protein precipitation with acetonitrile. LC-MS/MS was adopted. The determination were separated on Thermo Hypercarb column with mobile phase consisted of acetonitrile：arnmonium formate-formic acid at a flow rate of 0.40 mL-min^-1（gradient elution）. A tandem mass spectrometer equipped with electrospray ionization source （ESI） was used as detector and operated in the positive ion mode. Multiple Reaction Monitoring （MRM） using the precursor/production combinations of m/z 203.1→172.1, m/z 203.1→46.1 and rrdz 272.2→171 were used to quantify SDMA, ADMA and dextromethorphan, respectively. RESULTS：The linear ranges were 25-500 ng· mL^-1 for SDMA and ADMA uniformly. The lowest limits of quantitation of two compounds were 25 ng·mL^-1. Average method recovery rate was more than 97% and RSDs of intra-day and inter-day were lower than 17%. CONCLUSION： The method is proved to be specific, sensitive, accurate and rapid. It is suitable for rapid determination of biological samples.