A method for determination of amino acids in the formula of traditional Chinese medicine (TCM) by capillary electrophoresis (CE) with detection of laser-induced fluorescence (LIF) have been developed. Fifteen amino acids in the formula of the Chinese traditional medicine which derivatized with fluorescein isothiocyanate were finely separated and determinated by CE with borate buffer containing α-cyclodextrin as buffer additive. The separation parameters were investigated to give an optimal experimental conditions: borate buffer (80 mmol/L, pH 9.2) containing 45 mmol/L α-cyclodextrin; applied voltage, 20 kV; column temperature, 22 ℃. All amino acids were separated within 50 min. All amino acid-FITC derivatives is linear in the concentration range from 73.5 to 2900 nmol/L (r2＝0.9906～0.9998). The relative standard deviations (n＝6) of the method were 0.8%～3.0% for migration time and 0.7%～5.7% for peak area except cysteine (5.7%). The detection limits for amino acids were determined in the range from 3.5 to 35 nmol/L at a signal-to-noise ratio of three. This method allows to determining the amino acids in formula of TCM with high sensitivity.

Key words: capillary electrophoresis, laser-induced fluorescence, traditional Chinese medicine, amino acids