N‐(2‐Methoxybenzyl)‐2,5‐dimethoxyphenethylamines (NBOMes) are synthetic phenethylamine derivatives emerging on the global drug market and reported to be associated with untoward effects in people who use drugs. Its action involves agonism at serotonin 5‐HT_2A receptors, affecting cognitive and behavioral processes. However, certain isomers of NBOMes may not show any psychoactive effects. They are not controlled by legislation and can be tested as pharmaceutical drugs. This study deals with the differentiation among positional isomers of 25H‐NBOMe differing in the position of the two methoxy groups in the phenylethyl moiety of the molecule, using chromatography–mass spectrometry methods. The gas chromatography analysis showed that the isothermal mode was more efficient than the usually applied temperature‐programming mode for the separation of the mentioned isomers. Electron ionization mass spectra of 25H‐NBOMe isomers were highly similar, often resulting in a high probability of erroneous identification. However, mass spectra of their trifluoroacetyl or pentafluoropropanoyl derivatives were easily identified as they contained fragments with many significant differences. The proposed analysis using liquid chromatography–tandem mass spectrometry could distinguish the isomers of 25H‐NBOMe without the need for any derivatization.

中文翻译：

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N-（2-甲氧基苄基）-2-（二甲氧基苯基）乙胺系列色谱中的位置异构体的合成，分析特征的鉴别，色谱-质谱法测定。

N-（2-甲氧基苄基）-2,5-二甲氧基苯乙胺（NBOMes）是在全球药物市场上出现的合成苯乙胺衍生物，据报告与使用毒品的人的不良影响有关。其作用涉及5-羟色胺5-HT _2A的激动作用受体，影响认知和行为过程。但是，NBOMes的某些异构体可能没有表现出任何精神活性。它们不受立法控制，可以作为药物进行测试。本研究使用色谱-质谱法研究了25H-NBOMe的位置异构体之间的差异，该异构体的区别在于分子的苯乙基部分中两个甲氧基的位置不同。气相色谱分析表明，等温模式比通常使用的温度编程模式更有效地分离上述异构体。25H-NBOMe异构体的电子电离质谱非常相似，通常导致错误识别的可能性很高。然而，它们的三氟乙酰基或五氟丙酰基衍生物的质谱很容易确定，因为它们包含具有许多显着差异的片段。使用液相色谱-串联质谱法进行的拟议分析可以区分25H-NBOMe的异构体，而无需任何衍生化。