ABSTRACT
OBJECTIVE: To establish headspace capillary gas chromatography for the content determination of 3 kinds of residual organic solvent (furanidine,methanol and ethanol) in betamethasone sodium phosphate raw material.METHODS: The sample was dissolved in water and n-propanol was used as internal standard.The residual solvent in betamethasone sodium phosphate was separated on HP-INNOWAX (PEG) capillary column with column temperature set at 60 ℃.The injector temperature and FID detector temperature were controlled at 180 ℃ and 250 ℃,respectively.The carried gas was nitrogen at flow rate of 1.0 mL?min-1.The splitting-ratio was 10 ∶ 1.The containers of head-space injector were in equilibrium at 80 ℃ for 30 min.Injection time was 1 min.RESULTS: With this chromatographic condition,those solvents could be separated completely.The linear range were 0.014 4～0.071 8 mg?mL-1 for furanidine,0.060～0.300 mg?mL-1 for methanol and 0.099 3～0.497 mg?mL-1 for ethanol.The average recovery were 103.7% (RSD=0.53%,n=6),95.8% (RSD=0.30%,n=6) and 95.0% (RSD=0.48%,n=6) respectively.The minimum quantitation limit were 0.057 3 ?g?mL-1,0.486 ?g?mL-1,0.145 ?g?mL-1,respectively.3 kinds of residual organic solvents were all in line with the standard stated in Chinese Pharmacopeia.CONCLUSION: The established method is simple,sensitive and accurate for the content determination of residual solvents in betamethasone sodium phosphate raw material.