School of Pharmaceutical Sciences, University of Geneva , University of Lausanne, Life Sciences Mass Spectrometry, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland.
Anal Chem. 2013 Dec 17;85(24):11771-9. doi: 10.1021/ac4020353. Epub 2013 Dec 2.
The present work describes an alternative generic approach to LC-MS for the analysis of drugs of abuse as well as their metabolites in post-mortem tissue samples. The platform integrates liquid extraction surface analysis (LESA) for analytes tissue extraction followed by differential ion mobility spectrometry (DMS) mass spectrometry for analytes gas phase separation. Detection is performed on a triple quadrupole linear ion trap using the selected reaction monitoring mode for quantification as well as product ion scan mode for structural confirmatory analyses. The major advantages of the platform are that neither chromatographic separation nor extensive sample preparation are required. In DMS the combination of a high separation voltage (i.e., up to 4 kV) together with organic modifiers (e.g., alcohols, acetonitrile, acetone) added in the drift gas is required to achieve the separation of isomeric metabolites, such as the ones of cocaine and tramadol. DMS also separates morphine from its glucuronide metabolites, which allows for preventing the overestimation of morphine in case of fragmentation of the glucuronides in the atmospheric-to-vacuum interface of the mass spectrometer. Cocaine, opiates, opioids, amphetamines, benzodiazepines and several of their metabolites could be identified in post-mortem human kidney and muscle tissue based on simultaneous screening and confirmatory analysis in data-dependent acquisition mode using an analyte-dependent compensation voltage to selectively transmit ions through the DMS cell to the mass analyzer. Quantitative performance of the LESA-DMS-MS platform was evaluated for cocaine and two of its metabolites spotted onto a tissue section using deuterated internal standard. Analyte's responses were linear from 2 to 1000 pg on tissue corresponding to a limit of detection in the order of nanograms of analyte per gram of tissue. Accuracy and precision based on QC sample was found to be less than 10%. Replicate analyses of cocaine and its metabolites in forensic samples showed an intra- and inter-sections variability of less than 25%.
本工作描述了一种替代的 LC-MS 通用方法，用于分析死后组织样品中的药物滥用物及其代谢物。该平台集成了用于分析物组织提取的液体萃取表面分析 (LESA)，以及用于分析物气相分离的差分离子迁移谱 (DMS) 质谱。检测是在三重四极线性离子阱上进行的，使用选择反应监测模式进行定量，以及产物离子扫描模式进行结构确证分析。该平台的主要优点是既不需要色谱分离，也不需要广泛的样品制备。在 DMS 中，需要高分离电压（即高达 4 kV）与在漂移气体中添加的有机改性剂（如醇、乙腈、丙酮）相结合，以实现异构体代谢物的分离，如可卡因和曲马多的代谢物。DMS 还将吗啡与其葡萄糖醛酸代谢物分离，这可以防止在质谱仪的大气压-真空界面中葡萄糖醛酸代谢物发生碎片时高估吗啡。基于在数据依赖采集模式下使用分析物依赖的补偿电压选择性地将离子传输通过 DMS 细胞到质量分析仪，对死后人肾和肌肉组织中的可卡因、阿片类、类阿片类、苯丙胺、苯二氮䓬和它们的几种代谢物进行了同时筛选和确证分析，可以对其进行鉴定。使用氘代内标在组织切片上点样可卡因和两种代谢物，对 LESA-DMS-MS 平台的定量性能进行了评估。在对应于组织中纳克级分析物/克组织的检测限的范围内，组织上的分析物响应从 2 到 1000 pg 呈线性。基于 QC 样品的准确性和精密度发现小于 10%。在法医样本中可卡因及其代谢物的重复分析显示出低于 25%的内和间交叉变异性。
