In order to establish the quality control system of retigabine active substances,a headspace gas chromatographic method was established and validated for the determination of residual solvents of ethanol,hexane,tetrahydrofuran and triethylamine in retigabine active substances,by using FID as the detector and N,N-dimethylformamide as sample solvent.The detection of four residual solvents was performed on a DB-624 capillary column with vial equilibration temperature of 110 ℃ and equilibration time of 15 min.The limits of detection(LOD) for ethanol,hexane,tetrahydrofuran and triethylamine were 0.007 5%,0.000 48%,0.002 4% and 0.01%,respectively.The relative standard deviations(RSDs) of peak areas were below 2.1%.The average recoveries were in the range of 100%-102%, and the correlation coefficients were above 0.995.The result indicated that the method showed the advantages of high sensitivity,good accurancy and linearity.The established method was applied in the quality control of three batches of retigabine,and only ethanol and hexane were checked out with the highest residual level of 0.149% and 0.022%,respectively,which did not exceed the limited quantity. |