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∶ammonium 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 m/z 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.