The analysis of volatile organic compounds (VOCs) within breath for noninvasive disease detection and monitoring is an emergent research field that has the potential to reshape current clinical practice. However, adoption of breath testing has been limited by a lack of standardization. This protocol provides a comprehensive workflow for online and offline breath analysis using selected ion flow tube mass spectrometry (SIFT-MS). Following the suggested protocol, 50 human breath samples can be analyzed and interpreted in <3 h. Key advantages of SIFT-MS are exploited, including the acquisition of real-time results and direct compound quantification without need for calibration curves. The protocol includes details of methods developed for targeted analysis of disease-specific VOCs, specifically short-chain fatty acids, aldehydes, phenols, alcohols and alkanes. A procedure to make custom breath collection bags is also described. This standardized protocol for VOC analysis using SIFT-MS is intended to provide a basis for wider application and the use of breath analysis in clinical studies.

分析呼吸中的挥发性有机化合物（VOC）以进行无创疾病检测和监测是一个新兴的研究领域，有可能重塑当前的临床实践。然而，呼气测试的采用因缺乏标准化而受到限制。该协议提供了使用选定离子流管质谱 (SIFT-MS) 进行在线和离线呼吸分析的全面工作流程。按照建议的方案，可以在 3 小时内分析和解释 50 个人类呼吸样本。 SIFT-MS 的主要优势得到充分利用，包括实时结果采集和直接化合物定量，无需校准曲线。该协议包括为针对特定疾病的挥发性有机化合物（特别是短链脂肪酸、醛类、酚类、醇类和烷烃）进行针对性分析而开发的方法的详细信息。还描述了制作定制呼吸收集袋的程序。这种使用 SIFT-MS 进行 VOC 分析的标准化协议旨在为呼吸分析在临床研究中的更广泛应用和使用提供基础。