Determination of residual solvents in ibuprofen by headspace GC

OBJECTIVE To establish a method for determining residual solvents such as ethanol and 1,2 dichloroethane in ibuprofen by headspace gas chromatography.METHOD The GC was equipped with a headspace injector and a flame ionization detector. A 0.53 mm×30 m HP-624 chromatographic column (coated with 94% dimethylpolysiloxane and 6% cyanopropylpolysiloxane stationary phase) was adopted.The carrier gas was nitrogen.The assay of residual solvents were calculated according to the external standard method.RESULTS Only ethanol was found in the sample of ibuprofen. The standard curves were linear over the ranges of 0.43～42.9 μg·mL -1 ( r =0.999 4) for ethanol and 0.02～2.14 μg·mL -1 ( r =0.997 2)for 1,2 dichloroethane,respectively.The limits of quantitation were 0.4 μg·mL -1 for ethanol and 0.05 μg·mL -1 for 1,2 dichloroethane,respectively.The average recoveries were 95.0%( RSD =2.0%, n =5) for ethanol and 98.8%( RSD =2.7, n =5)for 1,2 dichloroethane.CONCLUSION This method appeared to be sensitive,accurate,repeatable and easy to op erate.