Determination of excitatory amino acids in biological fluids by capillary electrophoresis with optical fiber light-emitting diode induced fluorescence detection

The capillary electrophoresis (CE) system with optical fiber light-emitting diode (optical fiber LED) induced fluorescence detector was developed for the analysis of the excitatory amino acids (EAAs) tagged with naphthalene-2,3-dicarboxaldehyde (NDA). The separation of EAAs was carried out in an uncoated fused-silica capillary (50 cm x 75 mu m i.d.) with a buffer of 10 mM borate at pH 9.3 and an applied voltage of 20 kV. High sensitivity was obtained by the use of optical fiber LED induced fluorescence detector with a violet LED as the excitation light source. The limits of detection (S/N = 3) for glutamic acid (Glu) and aspartic acid (Asp) were 2.1 x 10(-8) and 2.3 x 10(-8) M, respectively. The detection approach was successfully applied to the analysis of Glu and Asp in biological fluids including human serum, rabbit serum and human cerebrospinal fluid (CSF) with satisfactory results. (c) 2006 Elsevier B.V. All rights reserved.