Abstract Several New Psychoactive Substances (NPS) have appeared on the drug market, following a new trend of drug consumption. Nuclear Magnetic Resonance (NMR) has been used, especially in the case of forensic analysis, as a tool for unambiguous structure determination of unknown NPS. The quantification of NPS in complex mixtures is, however, a very challenging task, especially in the absence of certified reference materials (CRM). In this work, we applied a quantitative 1H NMR (1H-qNMR) methodology performed without certified analytes for quantification of twelve NPS samples seized by the Brazilian Federal Police. The molecular structure of NPS samples were first confirmed by mono and bidimensional 1H and 13C NMR with unequivocally assigned signals, which allowed for the discrimination of constitutional isomers. A detailed compilation of NMR spectroscopic data showed that these NPS samples belong to cathinones, phenethylamines, and tryptamines groups. The quantitative analyses showed high precision (RSD = 2.67%) and low uncertainty (from 0.44% to 0.37%, with k = 2, 95% confidence). The NPS samples exhibited sufficient stability for a period of 48 h, which is longer than the experimental time frame and, therefore, assures the reliability and validity of the obtained results. Evaluation of some other figures of merit (selectivity, limits of quantification and detection) was also performed and confirmed the proposed method presents suitable and reproducible results. These achievements suggest the present methodology is highly adequate for forensic purposes, attaining excellent precision and accuracy, even in the absence of CRM.

中文翻译：

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定量核磁共振作为分析新精神活性物质的工具

摘要 随着毒品消费的新趋势，毒品市场上出现了几种新型精神活性物质（NPS）。核磁共振 (NMR) 已被用作确定未知 NPS 的明确结构的工具，特别是在法医分析的情况下。然而，复杂混合物中 NPS 的量化是一项非常具有挑战性的任务，尤其是在没有经过认证的参考材料 (CRM) 的情况下。在这项工作中，我们应用了定量 1H NMR (1H-qNMR) 方法，在没有经过认证的分析物的情况下对巴西联邦警察缉获的 12 个 NPS 样品进行了定量。NPS 样品的分子结构首先通过具有明确指定信号的单维和二维 1H 和 13C NMR 确认，这允许区分构成异构体。核磁共振光谱数据的详细汇编表明，这些 NPS 样品属于卡西酮、苯乙胺和色胺组。定量分析显示高精度 (RSD = 2.67%) 和低不确定性（从 0.44% 到 0.37%，k = 2，95% 置信度）。NPS 样品在 48 小时内表现出足够的稳定性，这比实验时间框架长，因此保证了所得结果的可靠性和有效性。还对其他一些品质因数（选择性、定量限和检测限）进行了评估，并确认所提出的方法提供了合适且可重现的结果。这些成就表明，即使在没有 CRM 的情况下，目前的方法也非常适合法医目的，获得出色的精确度和准确度。