本報告以固相萃取及甲基衍生化方法來分析尿中大麻代謝物11-nor-9-carboxy-△9-tetrahy-drocannabinol(9-THC-COOH)，用以判定受檢者是否使用大麻。d3-9-THC-COOH為內標準品，並以氣相層析質譜儀中之離子監測法(selected ion monitoring)做定性及定量分析。監測9-THC-COOH離子為m/z 313,357,372;d3-9-THC-COOH離子為m/z 316,360,375。5mL空白尿液配製濃度15 ng/mL之9-THC-COOH時，其固相萃取之回收率大於90%。以單點校正方式定量分析，最低可檢濃度為2.09 ng/mL;線性範圍位於4.18 ng/mL-376ng/mL間;而線性範圍內之日間精密度試驗其變異係數(Coefficient of variation)為1.49%-8.03%。

　　　　　A specimen pretreatment procedure, combining solid-phase extraction andmethylation, was developed for the analysis of 11-nor-9-carboxy-△9-tetrahydrocannabinol (9-THC-COOH) in urine for monitoring marijuana exposure. d3-11-Nor-9-carboxy-△9-tetrahydrocannabinol (d3-9-THC-COOH) was used as aninternal standard, while the now universal selected ion monitoring gaschromatography-mass spectrometry approach was used for detection (m/z 313, 357, 372and 316, 360, 375 for 9-THC-COOH and d3-9-THC-COOH, respectively.) and quantitation(m/z 372 and 375 for 9-THC-COOH and d3-9-THC-COOH, respectively). The effectivenessof the overall procedure was evaluated. One of the extraction columns evaluatedachieved > 90% recovery of the analyte in 5-mL drug-free urine fortified with 15 ng/mL9-THC-COOH. Using the one-point calibration approach, the overall protocol achievedthe following analytical parameters: detection limit: 2.09 ng/mL; limit ofquantitation: 4.18 ng/mL; upper end of linear range: 376 ng/mL (or better); interdayprecision: 1.49-8.03% CV in th 4.18--376 ng/mL concentration range studied.