Greer Cullen, Clowers Brian H
Department of Chemistry, Washington State University, Pullman, Washington 99163, United States.
J Am Soc Mass Spectrom. 2023 Aug 2;34(8):1545-1548. doi: 10.1021/jasms.3c00131. Epub 2023 Jul 5.
When operated as a standalone analytical device, traditional drift tube ion mobility spectrometry (IMS) experiments require high-speed, high-gain transimpedance amplifiers to record ion separations with sufficient resolution. Recent developments in the fabrication of charge-sensitive cameras (e.g., IonCCD) have provided key insights for ion beam profiling in mass spectrometry and even served as detectors for miniature magnetic sector instruments. Unfortunately, these platforms have comparatively slow integration times (multiple ms), which largely precludes their use for recording ion mobility spectra, where sampling rates into the 10s of kHz are generally required. As a result, experiments that simultaneously probe the longitudinal and transverse mobility of an injected species using an array detector have not been reported. To address this duty-cycle mismatch, a frequency encoding strategy is used to evaluate ion swarm characteristics, while directly capturing ion mobility information using the Fourier transform. This apparatus described allows the ion beam to be profiled over the full course of the experiment and establishes the foundation to examine axial and longitudinal drift velocities simultaneously.
当作为独立的分析设备运行时，传统的漂移管离子迁移谱（IMS）实验需要高速、高增益跨阻放大器来记录具有足够分辨率的离子分离情况。电荷敏感相机（如IonCCD）制造方面的最新进展为质谱中的离子束分析提供了关键见解，甚至还用作微型磁扇形仪器的探测器。不幸的是，这些平台的积分时间相对较长（数毫秒），这在很大程度上排除了它们用于记录离子迁移谱的可能性，因为记录离子迁移谱通常需要高达数十千赫兹的采样率。因此，尚未有使用阵列探测器同时探测注入物种的纵向和横向迁移率的实验报道。为了解决这种占空比不匹配的问题，采用了一种频率编码策略来评估离子群特性，同时使用傅里叶变换直接捕获离子迁移信息。所描述的该装置能够在整个实验过程中对离子束进行分析，并为同时检查轴向和纵向漂移速度奠定了基础。
