Marais Adriaan A S, Laurens Johannes B
Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa.
Forensic Sci Int. 2009 Jan 10;183(1-3):78-86. doi: 10.1016/j.forsciint.2008.10.021. Epub 2008 Dec 10.
Amphetamine and related derivatives are widely abused central- and psychostimulants. Detection of certain derivatives, such as methcathinone, by commonly available immunoassay screening techniques is insufficient. Multi-analyte confirmations for amphetamine type stimulants are therefore required, but traditional gas chromatography-mass spectrometry methods necessitate lengthy analytical procedures with prolonged sample turn-around times. A validated rapid GC-MS assay for urinary confirmation of amphetamine, methamphetamine, methcathinone, ephedrine, norephedrine, methylenedioxyamphetamine, methylenedioxymethamphetamine, methylenedioxyethylamphetamine and N-methyl-1-(3,4 methylenedioxyphenyl)-2-butanamine is reported. The method entailed in situ derivatization of urine specimens by extractive acylation with pentafluoropropionic anhydride, followed by rapid chromatography on a microbore capillary column. Analytes were separated in less than 3 min and quantified simultaneously by selected-ion monitoring using stable isotope substituted internal standards. The total instrument cycle-time was 6 min per sample. The limits of detection were between 1.5 ng/mL and 6.25 ng/mL for the various analytes. Intermediate precision and accuracy were in the range of 6.3-13.8% and 90.5-107.3% for the respective analytes at the lower limit of quantitation, and between 5.8-12.6% and 95.4-103.1% for the high control. Long-term storage of methcathinone positive specimens at -20 degrees C proved insufficient stability of this analyte. The proposed assay is precise and accurate for confirmation of amphetamine and derivatives in urine. The complementary approach of extractive-derivatization and fast GC-MS analysis is especially applicable in routine clinical settings where reduced sample turn-around times are required. Further investigation of cathinone as a possible metabolite of methcathinone is warranted, based on results from analyzed authentic urine samples.
苯丙胺及其相关衍生物是广泛滥用的中枢神经兴奋剂和精神兴奋剂。采用常用的免疫分析筛查技术检测某些衍生物（如甲卡西酮）并不充分。因此，需要对苯丙胺类兴奋剂进行多分析物确证，但传统的气相色谱 - 质谱法需要冗长的分析程序，样品周转时间较长。本文报道了一种经过验证的快速气相色谱 - 质谱法，用于尿液中苯丙胺、甲基苯丙胺、甲卡西酮、麻黄碱、去甲麻黄碱、亚甲二氧基苯丙胺、亚甲二氧基甲基苯丙胺、亚甲二氧基乙基苯丙胺和N - 甲基 - 1 -（3,4 - 亚甲二氧基苯基）- 2 - 丁胺的确证。该方法包括用五氟丙酸酐进行萃取酰化对尿液标本进行原位衍生化，然后在微径毛细管柱上进行快速色谱分析。分析物在不到3分钟内分离，并使用稳定同位素取代的内标通过选择离子监测同时进行定量。每个样品的仪器总循环时间为6分钟。各种分析物的检测限在1.5 ng/mL至6.25 ng/mL之间。在定量下限处，各分析物的中间精密度和准确度分别在6.3 - 13.8%和90.5 - 107.3%范围内，高浓度对照品的中间精密度和准确度分别在5.8 - 12.6%和95.4 - 103.1%之间。在 - 20℃下长期储存甲卡西酮阳性标本证明该分析物稳定性不足。所提出的方法对于尿液中苯丙胺及其衍生物的确证是精确且准确的。萃取衍生化和快速气相色谱 - 质谱分析的互补方法特别适用于需要缩短样品周转时间的常规临床环境。基于对真实尿液样本的分析结果，有必要进一步研究去甲伪麻黄碱作为甲卡西酮可能代谢物的情况。
