Determination of 6 residual solvents in selexipag by headspace gas chromatography

A headspace gas chromatography method was developed for the determination of six residual solvents including methanol, ethanol, acetone, dichloromethane, tetrahydrofuran and toluene residues in selexipag to provide the experimental basis for its quality control. The samples were separated on Kromat PC-624(V)silica capillary column(30. 0 m×0. 32 mm, 1. 8 μm)using temperature programming. The column temperature was kept at 40 °C for 5 min initially, and then raised to 180 °C at the rate of 20 °C /min and subsequently sustained for 5 min. FID detector temperature was 250 °C and injection temperature was 200 °C. The split ratio was 20 ∶1. The six residual solvents are separated completely under the given chromatographic conditions with a good linearity(r=0. 998 2-1. 000); the results of precision, repeatability and stability experiments met the requirement, and the mean recoveries of all solvents were in the range of 96. 67%-101. 7%. The analytical method is simple, accurate and sensitive, and it can be used for the determination of residual solvents in selexipag.