Ion mobility spectrometer are typically equipped with atmospheric pressure chemical ionization (APCI) sources operated at ambient pressure. However, classical APCI ion mobility spectrometers suffer from a limited ionization yield for nonpolar substances with low proton affinity. This is mainly due to ion clustering processes, especially those that involve water molecules, inhibiting the ionization of these substances.

中文翻译：

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在高动能离子迁移谱（HiKE‐IMS）中由低质子亲和性物质形成正产物离子

离子迁移谱仪通常配备在环境压力下运行的大气压化学电离（APCI）源。但是，对于质子亲和力低的非极性物质，传统的APCI离子迁移谱仪的电离收率有限。这主要是由于离子聚集过程，尤其是涉及水分子的离子聚集过程，抑制了这些物质的电离。