Sysoev Alexey, Adamov Alexey, Viidanoja Jyrki, Ketola Raimo A, Kostiainen Risto, Kotiaho Tapio
Moscow Engineering Physics Institute (State University), Kashirskoe Shosse 31, Moscow, Russia.
Rapid Commun Mass Spectrom. 2004;18(24):3131-9. doi: 10.1002/rcm.1738.
An ion mobility spectrometer that can easily be installed as an intermediate component between a commercial triple-quadrupole mass spectrometer and its original atmospheric pressure ionization (API) sources was developed. The curtain gas from the mass spectrometer is also used as the ion mobility spectrometer drift gas. The design of the ion mobility spectrometer allows reasonably fast installation (about 1 h), and thus the ion mobility spectrometer can be considered as an accessory of the mass spectrometer. The ion mobility spectrometer module can also be used as an independently operated device when equipped with a Faraday cup detector. The drift tube of the ion mobility spectrometer module consists of inlet, desolvation, drift, and extraction regions. The desolvation, drift and extraction regions are separated by ion gates. The inlet region has the shape of a stainless steel cup equipped with a small orifice. Ion mobility spectrometer drift gas is introduced through a curtain gas line from an original flange of the mass spectrometer. After passing through the drift tube, the drift gas serves as a curtain gas for the ion-sampling orifice of the ion mobility spectrometer before entering the ion source. Counterflow of the drift gas improves evaporation of the solvent from the electrosprayed sample. Drift gas is pumped away from the ion source through the original exhaust orifice of the ion source. Initial characterization of the ion mobility spectrometer device includes determination of resolving power values for a selected set of test compounds, separation of a simple mixture, and comparison of the sensitivity of the electrospray ionization ion mobility spectrometry/mass spectrometry (ESI-IMS/MS) mode with that of the ESI-MS mode. A resolving power of 80 was measured for 2,6-di-tert-butylpyridine in a 333 V/cm drift field at room temperature and with a 0.2 ms ion gate opening time. The resolving power was shown to be dependent on drift gas flow rate for all studied ion gate opening times. Resolving power improved as the drift gas flow increased, e.g. at a 0.5 ms gate opening time, a resolving power of 31 was obtained with a 0.65 L/min flow rate and 47 with a 1.3 L/min flow rate for tetrabutylammonium iodide. The measured limits of detection with ESI-MS and with ESI-IMS/MS modes were similar, demonstrating that signal losses in the IMS device are minimal when it is operated in a continuous flow mode. Based on these preliminary results, the IMS/MS instrument is anticipated to have potential for fast screening analysis that can be applied, for example, in environmental and drug analysis.
研发出了一种离子淌度谱仪，它能够轻松安装在商用三重四极杆质谱仪及其原始大气压电离（API）源之间作为中间组件。质谱仪的帘气也用作离子淌度谱仪的漂移气。离子淌度谱仪的设计允许进行相当快速的安装（约1小时），因此该离子淌度谱仪可被视为质谱仪的附件。当配备法拉第杯检测器时，离子淌度谱仪模块也可以用作独立运行的设备。离子淌度谱仪模块的漂移管由入口、去溶剂化、漂移和提取区域组成。去溶剂化、漂移和提取区域由离子门隔开。入口区域呈配有小孔的不锈钢杯形状。离子淌度谱仪的漂移气通过来自质谱仪原始法兰的帘气线路引入。在通过漂移管后，漂移气在进入离子源之前用作离子淌度谱仪离子采样孔的帘气。漂移气的逆流改善了电喷雾样品中溶剂的蒸发。漂移气通过离子源的原始排气孔从离子源抽出。离子淌度谱仪设备的初始表征包括确定一组选定测试化合物的分辨率值、分离简单混合物以及比较电喷雾电离离子淌度谱/质谱（ESI-IMS/MS）模式与ESI-MS模式的灵敏度。在室温下，对于2,6-二叔丁基吡啶，在333 V/cm的漂移场中，离子门打开时间为0.2 ms时，测得分辨率为80。结果表明，对于所有研究的离子门打开时间，分辨率都取决于漂移气流速。随着漂移气流速增加，分辨率提高，例如在离子门打开时间为0.5 ms时，对于碘化四丁铵，流速为0.65 L/min时分辨率为31，流速为1.3 L/min时分辨率为47。ESI-MS和ESI-IMS/MS模式下测得的检测限相似，这表明当IMS设备以连续流动模式运行时，IMS设备中的信号损失最小。基于这些初步结果，预计IMS/MS仪器在快速筛选分析方面具有潜力，例如可应用于环境和药物分析。
