A simple reversed-phase HPLC method for the estimation of dimethylarginines and homocysteine in plasma and serum

Elevated concentrations of asymmetric dimethylarginine, symmetric dimethylarginine and homocysteine are considered as common risk factors for cardiovascular diseases. A simple reversed-phase high-performance liquid chromatography method has been developed to simultaneously detect these biomarkers in plasma and serum. Straightforward sample preparation involves direct derivatization of deproteinized serum/plasma with phenyl isothiocyanate. Dimethylarginines and homocysteine are resolved using a 250 x 4.6 mm I.D, C-18 column and a linear gradient of sodium acetate buffer/acetonitrile. Calibration curves of peak area verses concentration are linear with correlation coefficients near unity. The intraday and interday precisions measured by coefficient of variation of peak areas were 1.34-9.7, 2.7-6.7 and 0.3-7.1 for asymmetric dimethylarginine, symmetric dimethylarginine and homocysteine, respectively. The recoveries of asymmetric dimethylarginine, symmetric dimethylarginine and homocysteine are above 86%. Minimal sample preparation, good recoveries and fast run time makes this method suitable for the analysis of plasma and serum.