Determination of methylated arginines in serum by a dispersive solid-phase extraction coupled with capillary electrophoresis-laser induced fluorescence detection

We describe a dispersive solid-phase ion exchange extraction method combined with capillary electrophoresis-laser induced fluorescence detection for the determination of asymmetric dimethylarginine, symmetric dimethylarginine, and monomethylarginine in serum samples. The methylated arginine-extracted resin beads were added into a mixed solution of 4-chloro-7-nitrobenzofuran acetonitrile solution and alkaline sodium borate solution (pH=10. 5) for the derivatization in a 60℃ water bath. The three derivatives were subjected to baseline separation in a fused silica capillary under the conditions of a separation electrolyte of 80 mmol/L phosphate (pH=2. 0) and a separation voltage of 20 kV. On the basis of the FDA bioanalytical method validation guidance, the method validation was conducted and the results were satisfactory. This method was used to determine the three methylated arginines in the serum samples from local hospital.