Quantification of Neurotransmitter Amino Acids in Human Serum by Capillary Electrophoresis with Laser-Induced Fluorescence Detection

Capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection is developed as a simple and sensitive method for the quantification of arginine (Arg), tyrosine (Tyr) and glutamic acid (Glu) in human serum. The separation conditions and the derivatization conditions with fluoresceinisothiocyanate (FITC) were investigated. Regression equations revealed a linear relationship (correlation coefficients: 0.9927–0.9998) between the peak area and concentration of each analyte. For the amino acids detected, 10^–10M detection limits were reached, and the levels of these amino acids in human serums were easily determined with recoveries of 93.5–106.5%.