Department of Pneumology, Sleep and Respiratory Medicine, Hemer Lung Clinic, Theo-Funccius-Str. 1, 58675 Hemer, Germany.
Witten/Herdecke University, Alfred-Herrhausen-Str. 50, 58448 Witten, Germany.
J Breath Res. 2023 Sep 4;17(4). doi: 10.1088/1752-7163/acf338.
Analyzing exhaled breath samples, especially using a highly sensitive method such as MCC/IMS (multi-capillary column/ion mobility spectrometry), may also detect analytes that are derived from exogenous production. In this regard, there is a discussion about the optimal interpretation of exhaled breath, either by considering volatile organic compounds (VOCs) only in exhaled breath or by additionally considering the composition of room air and calculating the alveolar gradients. However, there are no data on whether the composition and concentration of VOCs in room air are identical to those in truly inhaled air directly before analyzing the exhaled breath. The current study aimed to determine whether the VOCs in room air, which are usually used for the calculation of alveolar gradients, are identical to the VOCs in truly inhaled air. For the measurement of inhaled air and room air, two IMS, each coupled with an MCC that provided a pre-separation of the VOCs, were used in parallel. One device was used for sampling room air and the other for sampling inhaled air. Each device was coupled with a newly invented system that cleaned room air and provided a clean carrier gas, whereas formerly synthetic air had to be used as a carrier gas. In this pilot study, a healthy volunteer underwent three subsequent runs of sampling of inhaled air and simultaneous sampling and analysis of room air. Three of the selected 11 peaks (P4-unknown, P5-1-Butanol, and P9-Furan, 2-methyl-) had significantly higher intensities during inspiration than in room air, and four peaks (P1-1-Propanamine, N-(phenylmethylene), P2-2-Nonanone, P3-Benzene, 1,2,4-trimethyl-, and P11-Acetyl valeryl) had higher intensities in room air. Furthermore, four peaks (P6-Benzaldehyde, P7-Pentane, 2-methyl-, P8-Acetone, and P10-2-Propanamine) showed inconsistent differences in peak intensities between inhaled air and room air. To the best of our knowledge, this is the first study to compare simultaneous sampling of room air and inhaled air using MCC/IMS. The simultaneous measurement of inhaled air and room air showed that using room air for the calculation of alveolar gradients in breath analysis resulted in different alveolar gradient values than those obtained by measuring truly inhaled air.
分析呼出气样本，特别是使用 MCC/IMS（多毛细管柱/离子迁移谱）等高度敏感的方法，也可能检测到源自外源性产生的分析物。在这方面，有人讨论了最佳的呼出气解释方法，即仅考虑呼出气中的挥发性有机化合物（VOCs），还是同时考虑室内空气的组成并计算肺泡梯度。然而，目前还没有数据表明室内空气中 VOCs 的组成和浓度与在分析呼出气之前直接吸入的空气是否相同。本研究旨在确定用于计算肺泡梯度的室内空气中的 VOCs 是否与真正吸入的空气中的 VOCs 相同。为了测量吸入空气和室内空气，我们同时使用了两台 IMS，每台 IMS 都与一个 MCC 耦合，提供了 VOCs 的预分离。一台设备用于采集室内空气，另一台设备用于采集吸入空气。每个设备都与一个新发明的系统耦合，该系统可以清洁室内空气并提供清洁的载气，而以前必须使用合成空气作为载气。在这项初步研究中，一名健康志愿者进行了三次随后的吸入空气采样和同时的室内空气采样和分析。在 11 个选定的峰中，有 3 个（P4-未知、P5-1-丁醇和 P9-糠醛，2-甲基-）在吸气时的强度明显高于室内空气，4 个峰（P1-1-丙胺，N-（亚苄基）、P2-2-壬酮、P3-苯，1,2,4-三甲基-和 P11-乙酰缬氨酸）在室内空气中的强度更高。此外，还有 4 个峰（P6-苯甲醛、P7-戊烷，2-甲基-、P8-丙酮和 P10-2-丙胺）的峰强度在吸入空气和室内空气中的差异不一致。据我们所知，这是第一项使用 MCC/IMS 同时采集室内空气和吸入空气的研究。吸入空气和室内空气的同时测量表明，在呼气分析中使用室内空气计算肺泡梯度会导致与通过测量真正吸入的空气获得的肺泡梯度值不同。
