Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria.
Exposome Austria, Research Infrastructure and National EIRENE Node, 1090 Vienna, Austria.
Anal Chem. 2024 Aug 6;96(31):12710-12717. doi: 10.1021/acs.analchem.4c01630. Epub 2024 Jul 26.
Traditionally, chemical exposure has been assessed by low-resolution mass spectrometry via targeted approaches due to the typically extremely low concentration of such compounds in biological samples. Nevertheless, untargeted approaches are now becoming a promising tool for a broader investigation of the exposome, covering additional compounds, their biotransformation products, and possible metabolic alterations (metabolomics). However, despite broad compound coverage, untargeted metabolomics still underperforms in ultratrace biomonitoring analysis. To overcome these analytical limitations, we present the development of the first combined targeted/untargeted LC-MS method, merging MRM-HR and SWATH experiments in one analytical run, making use of Zeno technology for improved sensitivity. Multiple reaction monitoring transitions were optimized for 135 highly diverse toxicants including mycotoxins, plasticizers, PFAS, personal care products ingredients, and industrial side products as well as potentially beneficial xenobiotics such as phytohormones. As a proof of concept, standard reference materials of human plasma (SRM 1950) and serum (SRM 1958) were analyzed with both Zeno MRM-HR + SWATH and SWATH-only methodologies. Results demonstrated a significant increase in sensitivity represented by the detection of lower concentration levels in spiked SRM materials (mean value: 2.2 and 3 times lower concentrations for SRMs 1950 and 1958, respectively). Overall, the detection frequency was increased by 68% (19 to 32 positive detections) in the MRM-HR + SWATH mode compared to the SWATH-only. This work presents a promising avenue for addressing the outstanding key challenge in the small-molecule omics field: finding a balance between high sensitivity and broad chemical coverage. It was demonstrated for exposomic applications but might be transferred to lipidomics and metabolomics workflows.
传统上，由于生物样本中此类化合物的浓度通常极低，因此通过低分辨率质谱进行靶向方法来评估化学暴露。然而，非靶向方法现在正成为更广泛研究暴露组学的有前途的工具，涵盖了其他化合物、它们的生物转化产物以及可能的代谢改变（代谢组学）。然而，尽管具有广泛的化合物覆盖范围，非靶向代谢组学在痕量生物监测分析中仍表现不佳。为了克服这些分析限制，我们提出了开发首个组合靶向/非靶向 LC-MS 方法的方案，将 MRM-HR 和 SWATH 实验合并到一个分析运行中，利用 Zeno 技术提高灵敏度。优化了 135 种高度多样化的毒物的多重反应监测转换，包括霉菌毒素、增塑剂、PFAS、个人护理产品成分和工业副产品以及潜在有益的外源性化学物质，如植物激素。作为概念验证，使用 Zeno MRM-HR + SWATH 和仅 SWATH 两种方法分析了人血浆（SRM 1950）和血清（SRM 1958）标准参考物质。结果表明，灵敏度显著提高，在添加的 SRM 材料中检测到更低的浓度水平（平均值：SRM 1950 和 1958 的浓度分别低 2.2 和 3 倍）。总体而言，与仅 SWATH 相比，MRM-HR + SWATH 模式下的检测频率增加了 68%（19 个到 32 个阳性检测）。这项工作为解决小分子组学领域的突出关键挑战提供了一个有前途的途径：在高灵敏度和广泛的化学覆盖范围之间找到平衡。它已在暴露组学应用中得到证明，但可能转移到脂质组学和代谢组学工作流程中。
