DETERMINATION OF DIMETHYLATED ARGININES IN HUMAN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Using high-performance liquid chromatography (HPLC) with multigradient elution, NG,NG-dimethyl-L-arginine (asymmetric-DMA ADMA) and N-G,N'(G )-dimethyl-L-arginine (symmetric-DMA, SDMA) can be separated from huma n plasma samples. The dimethylarginine compounds in plasma, after extr action with a cation-exchange column, are converted to fluorescent der ivatives with o-phthaldialdehyde (OPA) in an alkaline medium and the d erivatives are separated simultaneously within 50 min on a reversed-ph ase column (Ultracarb 3 ODS(20)). The recoveries of ADMA and SDMA are over 80% and the method permits quantitative determination of dimethyl ated arginines at concentrations as low as 0.1 mu mol/1 in human plasm a.