Determination of residual organic solvents in tomoxetine hydrochloride by headspace gas chromatography

A method for the determination of five kinds of residual organic solvents in tomoxetine hydrochloride has been developed by headspace gas chromatography.A wide bore HP-fast GC residual solvent column was chosen for separation with FID detector.The external standard method was used for quantitative analysis.Several factors affecting the headspace determination were studied,including equilibrium temperature,equilibrium time and sample preparation.The standard curves were linear in the range of 0.41～8.10 μg/mL(r=0.9999) for methanol,0.15～3.00 μg/mL(r=0.9995) for diethyl ether,0.20～4.01 μg/mL(r=0.9991) for hexane,0.32～6.35 μg/mL(r=0.9999) for ethyl acetate and 0.36～7.11 μg/mL(r=0.9999) for tetrahydrofuran.The average recoveries for five residual organic solvents were between 96.30% and 105.47% with RSD(n=6) of precision in the range of 2.1%～3.7%.The detection limits of methanol, diethyl ether,hexane,ethyl acetate and tetrahydrofuran were 0.2,0.008,0.003,0.04 and 0.04 μg/mL respectively.