Abstract: A novel technique of liquid phase microextraction supported by hollow fiber membrane (LPME-HFM) was applied to extract tramadol in tap water, urine and human plasma. At room temperature (20 ℃), polyvinylidene fluoride hollow fiber membrane (PVDF-HFM) was employed. In the procedure of extraction, 4 μL of organic solvent (toluene) was used in individual extraction. Pethidine was used as the internal standard (IS) in the sample analysis by gas chromatography with flame ionization detector (GC-FID). The optimized conditions for tramadol extraction was as follows: toluene as organic solvent, 4 mL sample solution added with 0.1 mL of 1 mol/L NaOH solution, extraction time of 15 min, and stirring speed of 300 r/min. The sample solutions, containing a series of concentrations of tramadol, 0.05, 0.10, 0.50, 1.0, 5.0, 10.0 mg/L, were analyzed. The good linearities were obtained for water, human urine and human plasma samples with the correlation coefficients of 0.9997, 0.9948 and 0.9985, respectively. The detection limits can reach 0.01 mg/L for water and human urine and 0.05 mg/L for human plasma. The relative standard deviations (RSDs) were 10.6% and 5.15% for water, 18.1% and 4.03% for urine solution at the spiked levels of 0.1 and 1.0 mg/L. The RSDs were 16.6% and 4.15% for plasma solution at the spiked levels of 0.5 and 1.0 mg/L. In comparison with conventional method, this method is simple, sensitive, fast, inexpensive, and environmentally friendly. It can be applied to pharmaceutical and forensic analysis.

Key words: gas chromatography (GC), hollow fiber membrane, pethidine , tramadol, liquid phase microextraction