Abstract: Objective： To establish an HPLC method for determination of 3-aminophenol and free hydrazine in Pasiniazid tablets. Methods： 3-Aminophenol The eluate obtained was analyzed by HPLC method with Agilent ZORBAX SB-Aq (250 mm×4.6 mm，5μm)，using methanol-10%Tetrabutylammonium hydroxide-0.05 mol·L-1 NaH2PO4 buffer（100∶2∶900）as mobile phase， and the detection wavelength was set at 220 nm. Free hydrazine The eluate obtained was analyzed by HPLC method with Diamonsil Plus C18 (150 mm×4.6 mm，5 μm)， using 0.1% EDTA-acetonitrilr（30∶70）as mobile phase， and the detection wavelength was set at 310 nm. Results： 3-aminophenol and free hydrazine showed good linearity in the ranges of 0.101 0-20.19 μg·mL-1， 0.259 0-51.80 μg·mL-1 (r≥0.999 9) respectively. The detection limit were 0.1 ng、0.04 ng respectively. The average recovery values values of 3-aminophenol and free hydrazine of were 99.39%、99.16%（RSD≤1.0%，n=8）respectively. Conclusion： The method is simple with high accuracy and reproducible，which can be used for the determination of 3-aminophenol and free hydrazine in Pasiniazid tablets.

Key words: font-size:medium, ">Pasiniazid tablets； 3-aminophenol； Free hydrazine； High performance liquid chromatography(HPLC)