Simultaneous determination of l-arginine and dimethylarginines in human urine by high-performance liquid chromatography Original Research Article

l-Arginine (l-Arg), NG,NG-dimethylarginine (ADMA), NG,N′G-dimethylarginine (SDMA) can be simultaneously separated and measured from urine using o-phthaldialdehyde (OPA) as a fluorescent reagent by reversed-phase high-performance liquid chromatography. Extraction of sample was not required, and derivatization can be directly performed after deprotein of sample. OPA-derivatives were successfully resolved using a Nova-pak C18 column (150 mm×4.6 mm i.d.) with gradient program in 35 min. The mean recoveries of l-Arg, ADMA and SDMA were over 97%. The relative standard deviations were lower 4.6 and 0.32% for amount and retention time, respectively. The detection limits of the method are 1.0 pmol with signal-to-noise ratio is 3:1. Using this method, the levels of l-Arg, ADMA and SDMA in human urine were determined.