Abstract: A pre-column derivatization HPLC method for the analysis of 12 depression-related amino acids in rat plasma and brain tissue using 9,10-anthraquinone-2-sulfonyl chloride as derivatization reagent was developed.Rat plasma and brain tissue were deproteinated by acetonitrile and derivatized for only 5 min at room temperature by addition of Kolthoff buffer(pH 8.8)and derivatization reagent.The derivatives were separated on a C₁₈ column at 35 °C and detected at 254 nm.The mobile phase was acetonitrile and 20 mmol/L ammonium acetate buffer (pH 7.5) with a gradient program at 1.0 mL/min.Good linearity was achieved over the concentration range for each amino acid.The method has good sensitivity,accuracy and specificity,and can be used to analyze amino acids related with the depression in rat plasma and brain tissue.