Figure 4.
Separation of analytes in the dopamine metabolic pathway and monitoring concentration changes with the online MD-ME-EC system. Separation of analytes (100 µM each) dissolved in 15 mM phosphate. A direct connect scheme was employed and peak identities are indicated in the figure. A separation voltage of 2000 V, injection time of 1.5 s, perfusion flow rate of 1.0 µL/min, and separation buffer of 15 mM phosphate (pH 7.4), 15 mM SDS, and 2.5 mM boric acid were used. Inset demonstrates monitoring concentration change of L-DOPA over time, where the concentration of L-DOPA in a vial was increased through spiking, and sampled and analyzed on-line with the developed device (n = five injections for each concentration and a separation buffer of 15 mM phosphate (pH 7.4), 0.5 mM SDS, and 2.5 mM boric acid).