National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
J Am Soc Mass Spectrom. 2022 Sep 7;33(9):1784-1793. doi: 10.1021/jasms.2c00166. Epub 2022 Aug 25.
Chromatographic-less mass spectrometry techniques like direct analysis in real-time mass spectrometry (DART-MS) are steadily being employed as seized drug screening tools. However, these newer analytical platforms require new computational methods to best make use of the collected data. The inverted library search algorithm (ILSA) is a recently developed method designed specifically for working with mass spectra of mixtures collected with DART-MS and has been implemented as a function in the NIST/NIJ DART-MS data interpretation tool (DIT). This paper demonstrates how DART-MS and the ILSA/DIT can be used to analyze seized drug evidence, while discussing insights gathered during the evaluation of 92 adjudicated case samples. The evaluation verified that the combination of DART-MS and the ILSA/DIT can be used as an informative tool to help analysts screen seized drug evidence but also revealed several factors─such as the influence of incorporating multiple in-source fragmentation spectra and the effect of scoring thresholds─an analyst must consider while employing these methods. Use cases demonstrating the benefit of the nonscoring metrics provided by the ILSA/DIT and demonstrating how the ILSA/DIT can be used to identify novel substances are also presented. A summary of considerations for using the ILSA/DIT for drug screening concludes this paper.
像实时直接分析质谱（DART-MS）这样的无色谱质谱技术正被逐步用作缴获药物筛查工具。然而，这些新的分析平台需要新的计算方法来充分利用收集到的数据。反向库搜索算法（ILSA）是一种最近开发的方法，专门用于处理使用 DART-MS 采集的混合物的质谱，并已作为 NIST/NIJ DART-MS 数据解释工具（DIT）中的一个功能实现。本文演示了如何使用 DART-MS 和 ILSA/DIT 来分析缴获的药物证据，同时讨论了在评估 92 个裁决案例样本时收集到的见解。评估结果证实，DART-MS 和 ILSA/DIT 的组合可作为一种信息工具，帮助分析人员筛选缴获的药物证据，但也揭示了一些因素，如纳入多个源内碎裂光谱的影响以及评分阈值的影响，分析人员在使用这些方法时必须考虑这些因素。本文还提供了使用 ILSA/DIT 提供的非评分指标的优势的用例，并展示了如何使用 ILSA/DIT 来识别新物质。本文总结了使用 ILSA/DIT 进行药物筛选的注意事项。
