A versatile proton transfer reaction-mass spectrometry platform for online monitoring of VOCs.

质子转移反应质谱法（PTR-MS）是质谱法的一个专门分支，用于挥发性有机化合物（VOCs）的在线监测。市售的PTR-MS仪器的响应时间约为100 ms，并且在个位数pptv区域达到检测极限。它采用气相水合氢离子作为离子源试剂。这使得PTR-MS光谱仪非常适合在广泛的生物科学研究项目中对挥发性有机化合物进行快速、灵敏的分析，这些项目可以在线、同步、实时检测、监测和定量挥发性有机化合物。PTR-MS使用质子转移的“软”电离技术，从质子化水（h30 +）中转移质子，这是由离子源产生的离子束。在这种相互作用过程中，一个质子从水合氢离子转移到我们感兴趣的微量气体分子中，从而形成质子化并因此电离的分子。该反应在能量上适用于质子亲和度高于水的所有VOCs，因此适用于烷烃、烯烃、炔烃、芳烃和其他有机分子；因此，PTR-MS可以很好地覆盖挥发物。使用不同的试剂气体可以进一步增强这种覆盖范围；这可以通过快速切换，包括O2+， NO+， Kr+和Xe+。此外，将独特的PTR电离与飞行时间质谱相结合，可以实现高灵敏度和高分辨率的检测。因此，与现有的分析方法相比，PTR-MS具有很大的优势，它满足了当代生物科学项目的许多要求，例如快速连续监测。所要求的PTR-MS平台提供的原位和实时监测挥发物化学多样性的能力将为我们对生物系统基础机制的理解提供重要的新见解。这与BBSRC的战略重点是一致的，通过支持研究项目来解决合成生物学、生物能源、食品营养和健康、综合微生物组研究和工业生物技术（IB）战略方法方面的重大挑战。

Proton-transfer-reaction mass spectrometry (PTR-MS) is a specialized branch of mass spectrometry that is used for online monitoring of volatile organic compounds (VOCs). Commercially available PTR-MS instruments have a response time of about 100 ms and reach a detection limit in the single digit pptv region. It uses gas phase hydronium ions as ion source reagents. This makes PTR-MS spectrometers ideally suited for rapid and sensitive analysis of VOCs in a wide range of bioscience research programmes enabled by the online, simultaneous real-time detection, monitoring and quantification of VOCs. PTR-MS uses the 'soft' ionisation technique of proton transfer from protonated water (H3O+), which is produced as an ion beam by an ion source. During this interaction a proton transfers from the hydronium to the trace gas molecule of interest that leads to a protonated and hence ionised molecule. This reaction is energetically possible for all VOCs with a proton affinity higher than that of water and is thus amenable to alkanes, alkenes, alkynes, aromatics and other organic molecules; PTR-MS therefore provides good coverage of the volatilome. This coverage can be further enhanced with the use of different reagent gases; this is available via fast switching and includes O2+, NO+, Kr+ and Xe+. Furthermore, combining the unique PTR ionisation with Time-of-Flight MS permits for high-sensitivity and high-resolution detection. PTR-MS thus offers major advantages over current analysis methods and it meets many of the demands of contemporary bioscience programmes such as rapid continuous monitoring.The ability to monitor chemical diversity of the volatilome in situ and in real-time provided by the requested PTR-MS platform will provide major new insights towards our understanding of the underpinning mechanisms of biological systems. This aligns with BBSRC strategic priorities by underpinning research programmes that tackle major challenges in synthetic biology, bioenergy, food nutrition and health, integrative microbiome research and strategic approaches to industrial biotechnology (IB).