Omega-oxidation is a fatty acid degradation pathway that can occur alternatively to the dominant β-oxidation. The dysregulation of fatty acid oxidation has been related with a variety of diseases, termed fatty acid oxidation disorders. This work shows evidence for real-time detection in exhaled breath of the complete series of saturated linear ω-hydroxyalkanoic acids, ω-oxoalkanoic acids, and alkanedioic acids with carbon chain lengths of 5–15. We present a comprehensive analytical workflow using online and subsequent offline methods: secondary electrospray ionization mass spectrometry of exhaled breath and UHPLC-HRMS/MS experiments using exhaled breath condensate, respectively. By analyzing online breath measurements of 146 healthy individuals, we were able to obtain strong evidence for the correlation of these metabolite families. This enabled us to monitor the full ω-oxidation pathway in human exhaled breath. We could unambiguously identify these compounds, many of which have never been reported in breath so far. This comprehensive study on breath metabolites reinforces the notion of breath as a valuable source of information, which is underexploited in metabolomics.

中文翻译：

---

呼出气中脂肪族脂肪酸的ω-氧化产物的质谱检测

ω-氧化是一种脂肪酸降解途径，可以代替主要的β-氧化发生。脂肪酸氧化失调与多种疾病有关，称为脂肪酸氧化失调。这项工作显示了在呼气中实时检测碳链长度为5至15的饱和线性ω-羟基链烷酸，ω-氧代链烷酸和链烷二酸的完整序列的证据。我们提供了使用在线和后续离线方法的全面分析工作流程：呼气的二次电喷雾电离质谱和分别使用呼气冷凝物的UHPLC-HRMS / MS实验。通过分析146位健康个体的在线呼吸测量，我们能够获得有关这些代谢物家族相关性的有力证据。这使我们能够监测人类呼出气中的完整ω-氧化途径。我们可以明确地鉴定出这些化合物，到目前为止，尚未在呼吸中报道过许多化合物。这项关于呼吸代谢物的综合研究强化了呼吸这一重要信息来源的概念，而在代谢组学中该信息尚未得到充分利用。