Casteele Sofie R Vande, Bouche Marie-Paule L, Van Bocxlaer Jan F
Laboratory of Medical Biochemistry and Clinical Analysis, Vakgroep Bio-analysis, Ghent University, Ghent, Belgium.
J Sep Sci. 2005 Sep;28(14):1729-34. doi: 10.1002/jssc.200500108.
This paper describes the surplus value of a quadrupole-orthogonal acceleration TOF mass spectrometer, coupled to a liquid chromatographic separation system, for the unequivocal identification and structural elucidation of an unknown compound in the field of designer drugs. In a patient sample set (blood, tissues, vitreous humor, etc.), analyzed with a dedicated liquid chromatographic-fluorescence detection method for the determination of methylenedioxy amphetamine, methylenedioxy methamphetamine, and methylenedioxy ethylamphetamine (MDEA), a "strange" inexplicable peak appeared at a retention time not corresponding to any of our reference materials. Based on the identical excitation and emission wavelengths in detection, and a retention behavior comparable to MDEA, it was assumed that this unknown compound was an isomer of the recreational drug MDEA. With a simple and straightforward methodological crossover between LC fluorescence detection and LC-MS/MS, additional information for structural elucidation was easily obtained. Chromatographic separation was achieved on a Hypersil BDS C18 column (fluorescence detection part) and on a Hypersil BDS phenyl column (mass spectrometric detection part). MS showed that the unknown compound's molecular mass was identical to that of MDEA, and, in addition, its fragmentation pattern too proved quite similar to that of MDEA. A thorough literature overview and study of the fragmentation pattern by means of the MS/MS spectrum led to an evidence-based hypothesis of 3,4-methylenedioxy N,N-dimethylamphetamine (MDDM) being the unknown compound. To confirm this hypothesis, MDDM was synthesized and its presence in our biological sample was finally demonstrated by co-injection with alternatively synthesized MDDM and MDEA. This application shows the synergism between LC and MS in the elucidation of unknown compounds, nevertheless emphasizing the essence of chromatographic separation when dealing with isomers.
本文介绍了一种与液相色谱分离系统联用的四极杆正交加速飞行时间质谱仪的优势，用于明确鉴定和结构解析设计药物领域中的未知化合物。在一组患者样本（血液、组织、玻璃体液等）中，采用专门的液相色谱 - 荧光检测方法测定亚甲二氧基苯丙胺、亚甲二氧基甲基苯丙胺和亚甲二氧基乙基苯丙胺（MDEA）时，在一个与我们任何参考物质的保留时间均不对应的位置出现了一个“奇怪”的、无法解释的峰。基于检测中相同的激发和发射波长以及与MDEA相当的保留行为，推测该未知化合物是娱乐性药物MDEA的一种异构体。通过液相色谱荧光检测和液相色谱 - 串联质谱之间简单直接的方法交叉，很容易获得用于结构解析的额外信息。在Hypersil BDS C18柱（荧光检测部分）和Hypersil BDS苯基柱（质谱检测部分）上实现了色谱分离。质谱显示未知化合物的分子量与MDEA相同，此外，其碎片模式也与MDEA非常相似。通过对质谱/质谱谱图的碎片模式进行全面的文献综述和研究，得出了一个基于证据的假设，即未知化合物为3,4 - 亚甲二氧基 - N,N - 二甲基苯丙胺（MDDM）。为了证实这一假设，合成了MDDM，并通过与交替合成的MDDM和MDEA共注射，最终证明了其在我们生物样本中的存在。本应用展示了液相色谱和质谱在解析未知化合物方面的协同作用，但同时强调了在处理异构体时色谱分离的重要性。
