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首页> 外文期刊>Journal of mass spectrometry: JMS >Simultaneous screening of targeted and nontargeted contaminants using an LC-QTOF-MS system and automated MS/MS library searching
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Simultaneous screening of targeted and nontargeted contaminants using an LC-QTOF-MS system and automated MS/MS library searching

机译：使用LC-QTOF-MS系统和自动MS / MS库搜索同时筛查目标和非目标污染物

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摘要

Simultaneous high-resolution full-scan and tandem mass spectrometry (MS/MS) analysis using time of flight mass spectrometry brings an answer for increasing demand of retrospective and non-targeted data analysis. Such analysis combined with spectral library searching is a promising tool for targeted and untargeted screening of small molecules. Despite considerable extension of the panel of compounds of tandem mass spectral libraries, the heterogeneity of spectral data poses a major challenge against the effective usage of spectral libraries. Performance evaluation of available LC-MS/MS libraries will significantly increase credibility in the search results. The present work was aimed to evaluate fluctuation of MS/MS pattern, in the peak intensities distribution together with mass accuracy measurements, and in consequence, performance compliant with ion ratio and mass error criteria as principles in identification processes for targeted and untargeted contaminants at trace levels. Matrix effect and ultra-trace levels of concentration (from 50 ngl~(-1) to 1000ngl~(-1)) were evaluated as potential source of inaccuracy in the performance of spectral matching. Matrix-matched samples and real samples were screened for proof of applicability. By manual review of data and application of ion ratio and ppm error criteria, false negatives were obtained; this number diminished when in-house library was used, while with on-line MS/MS databases 100% of positive samples were found. In our experience, intensity of peaks across spectra was highly correlated to the concentration effect and matrix complexity. In turn, analysis of spectra acquired at trace concentrations and in different matrices results in better performance in providing correct and reliable identification.
机译：使用飞行时间质谱仪进行的同时高分辨率全扫描和串联质谱分析（MS / MS），为追溯和非目标数据分析的需求日益增长提供了答案。此类分析与光谱库搜索相结合是针对小分子进行靶向和非靶向筛选的有前途的工具。尽管串联质谱库的化合物组合有相当大的扩展，但是光谱数据的异质性对有效使用光谱库提出了重大挑战。可用的LC-MS / MS库的性能评估将大大提高搜索结果的可信度。本工作旨在评估MS / MS模式的波动，峰强度分布以及质量准确度测量，结果是符合离子比和质量误差标准的性能，是痕量目标污染物和非目标污染物鉴定过程中的原则水平。基质效应和浓度的超痕量水平（从50 ngl〜（-1）到1000ngl〜（-1））被评估为光谱匹配性能不准确的潜在来源。筛选与基质匹配的样品和真实样品，以证明其适用性。通过人工检查数据并应用离子比率和ppm误差标准，可以得到假阴性。使用内部文库时，该数字减少了，而使用在线MS / MS数据库，发现100％的阳性样本。根据我们的经验，整个光谱的峰强度与浓度效应和基质复杂度高度相关。反过来，对以痕量浓度和不同基质采集的光谱进行分析可以得到更好的性能，从而提供正确和可靠的识别。

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