Bollenbach Alexander, Hanff Erik, Beckmann Bibiana, Kruger Ruan, Tsikas Dimitrios
Institute of Toxicology, Core Unit Proteomics, Hannover Medical School, 30623 Hannover, Germany.
Institute of Occupational Medicine, Hannover Medical School, 30623 Hannover, Germany.
Anal Biochem. 2018 Sep 1;556:40-44. doi: 10.1016/j.ab.2018.06.021. Epub 2018 Jun 23.
Circulating and excretory N,N-dimethyl-l-arginine (symmetric dimethylarginine, SDMA) and N,N-dimethyl-l-arginine (asymmetric dimethylarginine, ADMA) are cardiovascular risk factors. Despite close chemical structures, the gas chromatography-mass spectrometry (GC-MS) measurement of SDMA is remarkably more difficult than that of ADMA for as yet unknown reasons. Here, we describe an improved GC-MS method for the quantitative determination of SDMA in human urine using commercially available N,N-di-[H]methyl-l-arginine (d-SDMA) as internal standard. The method is based on a single derivatization step with pentafluoropropionic anhydride (PFPA) in ethyl acetate (30 min, 65 °C) to N,N,N,O-tetrakis-pentafluoropropionyl derivatives, electron-capture negative-ion chemical ionization and selected-ion monitoring of the mass-to-charge (m/z) ions of m/z 456 for SDMA and m/z 462 for d-SDMA.
循环和排泄的N，N-二甲基-L-精氨酸（对称二甲基精氨酸，SDMA）和N，N-二甲基-L-精氨酸（不对称二甲基精氨酸，ADMA）是心血管危险因素。尽管化学结构相近，但由于尚不清楚的原因，用气相色谱-质谱法（GC-MS）测定SDMA比测定ADMA要困难得多。在此，我们描述了一种改进的GC-MS方法，以市售的N，N-二-[H]甲基-L-精氨酸（d-SDMA）作为内标，用于定量测定人尿中的SDMA。该方法基于在乙酸乙酯中用五氟丙酸酐（PFPA）进行单步衍生化（30分钟，65°C），生成N，N，N，O-四-五氟丙酰基衍生物，采用电子捕获负离子化学电离和对SDMA的质荷比（m/z）为456的离子以及d-SDMA的m/z为462的离子进行选择离子监测。
