RESUMEN
An easy, sensitive and quick method was established for simultaneously separating and determining stimulant, narcotics and antiestrogen in spiked human urine using gas chromatography-nitrogen phosphorous detection (GC-NPD). The urine sample was preprocessed by liquid-liquid extraction. Tert-butyl methyl ether and N-phenylamine were chosen as extraction solvent and internal standard for quantitation, respectively. That is, a standard stock mixture containing methylephedrine, meperidine, methadone, tamoxifen, fentanyl and N-phenylaniline was added into 5.0 mL urine samples and mixed uniformly, then 0.5 mL 5.0 mol/L NaOH, 3.0 g NaCl and 5.0 mL tert-butyl methyl ether were added and finally centrifuged. The extraction solution was dried under N2, redissolved by acetone and then determined by GC-NPD. The )j method showed the satisfactory linearity was between 0.022 - 20 mg/L, with the coefficient correlation from 0.9945 to 0.9998. The detection limits were in the range of 0.007 - 0.015 mg/ L, and the average recoveries in spiked urine were between 75.8% - 118.2% and the relative standard deviations were lower than 17.2%.