Song Qingyu, Xu Wei, Smith Scott A, Gao Liang, Chappell William J, Cooks R Graham, Ouyang Zheng
Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
J Mass Spectrom. 2010 Jan;45(1):26-34. doi: 10.1002/jms.1684.
In recent years, it has become increasingly interesting to understand the performance of mass spectrometers at pressures much higher than those employed with conventional operating conditions. This interest has been driven by several influences, including demand for the development of reduced-power miniature mass spectrometers, desire for improved ion transfer into and through mass spectrometers, enhanced-yield preparative mass separations, and mass filtering at the atmospheric pressure interface. In this study, an instrument was configured to allow for the performance characterization of a rectilinear ion trap (RIT) at pressures up to 50 mtorr with air used as the buffer gas. The mass analysis efficiency, mass resolution, isolation efficiency, and collision-induced dissociation (CID) efficiency were evaluated at pressures ranging from 1 to 50 mtorr. The extent of degradation of mass resolution, isolation efficiency and ion stability as functions of pressure were characterized. Also, the optimal resonance ejection conditions were obtained at various pressures. Operations at 50 mtorr demonstrated improved CID efficiency in addition to peak widths of 2 and 5 m/z units (full width at half-maximum, FWHM) for protonated caffeine (m/z 195) and Ultramark (m/z 1521) respectively.
近年来，了解质谱仪在远高于传统操作条件下的压力下的性能变得越来越有趣。这种兴趣受到多种因素的推动，包括对低功耗微型质谱仪开发的需求、改善离子进入和通过质谱仪的传输的愿望、提高制备性质量分离的产率以及在大气压接口处进行质量过滤。在本研究中，配置了一台仪器，以空气作为缓冲气体，在高达50 mTorr的压力下对直线离子阱（RIT）的性能进行表征。在1至50 mTorr的压力范围内评估了质量分析效率、质量分辨率、隔离效率和碰撞诱导解离（CID）效率。表征了质量分辨率、隔离效率和离子稳定性随压力变化的降解程度。此外，还获得了不同压力下的最佳共振喷射条件。在50 mTorr下操作时，除了质子化咖啡因（m/z 195）和超标记物（m/z 1521）的半高宽分别为2和5 m/z单位外，还显示出CID效率有所提高。
