Objective: To establish a method for the assay of naphthoquine by non-aqueous titration

so as to provide more data for the quantitative determination of naphthoquine. Method: The non-aqueous titration was carried out by using glacial acetic acid as solvent

α-naphthalphenol benzyl alcohol as indicator

and titrated with perchloric acid volumetric solution at a concentration of 0.1 mol·L-1.Meanwhile

the end point of titration was validated by auto- potentiometric titration

and study the precision

intermediate–precision

stability and recovery of the method were also studied

and compared the method with two other methods

UV and HPLC. Result: End point of the non-aqueous titration was obvious (blue→greenyellow)

which was also identified simultaneously by Auto-potentiometric titration. The average recovery was 100.0% with RSD 0.1% (n=6). The results of comparison showed little difference among the three kinds of methods. Conclusion: The method of non-aqueous titration has a good accuracy

repetitiveness and easy to carry out

which is suitable for the assay of naphthoquine.