Determination of 5 Kinds of Residual Organic Solvents in Thyroid Tablets by Headspace Capillary Gas Chromatography

OBJECTIVE:To establish a method for the content determination of 5 kinds of residual organic solvents in thyroid tablets,i.e.methanol,ethanol,acetone,ether and ethyl acetate.METHODS:Headspace capillary gas chromatography was adopted.The residual organic solvents were separated on DB-1 capillary column with FID detector.The carried gas was nitrogen.The injector temperature and detector temperature were controlled at 200 ℃ and 250 ℃,respectively.The column temperature was raised by program.The sample was dissolved in dimethyl sulfoxide.The containers of head-space injector were in equilibrium at 100 ℃ for 30 min,and the splitting-ratio was 10:1.RESULTS:The measured solvents were separated completely(r ranged 0.999 6～0.999 9).The detection limits were 0.6 μg·mL-1,2.0 μg·mL-1,1.0 μg·mL-1,0.2 μg·mL-1,0.1 μg·mL-1,respectively.The average recovery rates were 98.6%～100.3%(RSD=0.53%～1.32%).The residual organic solvents of 3 batches of samples were within standard range.CONCLUSION:The established method is simple,rapid,sensitive and accurate.It is suitable for the content determination of residual organic solvents in thyroid tablets.