[Hollow fiber liquid phase microextraction of tramadol from water and biological samples]

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 degrees C), polyvinylidene fluoride hollow fiber membrane (PVDF-HFM) was employed. In the procedure of extraction, 4 microL 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 mm, 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 0.999 7, 0.994 8 and 0.998 5, 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.