Objective: To study the determination methods for naphthoquine by Ultraviolet Spectrophotometry(UV) and High Performance Liquid Chromatography (HPLC)

to provide data for the quantitative determination of naphthoquine. Method: To UV

0.05 mol·L-1 hydrochloric acid was used to dissolve the sample then test at wavelength 341 nm.HPLC was achieved on a Diamonsil C18 column (4.6 mm×250 mm

5 μm) utilizing a mobile phase which consisted of acetonitrile and 0.25% diethylamine(pH 2.5)(23∶77). The flow rate was 0.8 mL·min-1

and the detection wavelength was at 342 nm. Result: To UV

naphthoquine has a good linearity at the range of 5.1-15.3 mg·L-1 (r=0.999 9)

and the average recovery is 100.0% with RSD 0.3%(n=9).As to HPLC

naphthoquine has a good linearity at the range of 0.16-0.8 μg (r=0.999 9)

and the average recovery was 99.9% with RSD 0.2%(n=9).The assay results among UV

HPLC and non-aqueous titration showed little difference. Conclusion: Both methods of UV and HPLC are suitable for the determination of naphthoquine.