According to the validation data for this method, the analysis of urine by SPE and PCI-GC-MS is suitable for the detection and quantification of KT in human urine. Extracted calibration curve of KT and NK were linear from 50 to 1000 ng/mL with correlation coefficient 0.99. The limit of quantitation of KT and NK was the first point of the calibration curve, 50 ng/mL, and the limits of detection, which were defined as the detection limits of the target and qualifier ion peaks on each mass chromatogram, was estimated to be 25 ng/mL in the full-scan modes. The values of accuracy for KT and NK at three different concentration levels were less than 15 percent. SPE is simple and requires less organic solvent than liquid-liquid extraction, and PCI-GC-MS can offer both qualitative and quantitative information for urinalysis of KT. The analytical method was applied to six KT suspected urine specimens and KT-administered rat urine, and the concentrations of KT and NK were determined. 3 tables, 7 figures, and 7 references