Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
J Am Soc Mass Spectrom. 2010 Mar;21(3):393-402. doi: 10.1016/j.jasms.2009.11.002. Epub 2009 Nov 13.
Mass analysis with islands of stability has been investigated with three linear quadrupole mass filters: two with 4% added hexapole fields constructed with equal diameter (quadrupole 4A) and unequal diameter (quadrupole 4B) rods, and a conventional round-rod quadrupole that has apparently been slightly damaged. Islands are formed by applying auxiliary quadrupole excitation. With the Mathieu parameter, a < 0, mass analysis with both quadrupoles with hexapole fields operated normally, i.e., without islands, gives only low resolution. A factor of 10 or more increase in resolution is possible with the use of stability islands. With a > 0, when quadrupole 4A is operated normally, peak shapes similar to that of a conventional quadrupole can be obtained at resolutions higher than 850. At lower resolutions, peaks are split. When quadrupole 4B is operated without islands, resolution up to 2000 is possible, but there are low mass tails and structure is formed on the peaks. With mass analysis with an island of stability, both quadrupoles 4A and 4B show peaks free of structure and without tails. Ion transmission is also improved with some operating conditions. With the conventional round-rod quadrupole, mass analysis with islands of stability increases the limiting resolution from 2500 to 4360. At a resolution of 2500, the transmission is increased by about two orders of magnitude. These results show that the use of islands of stability improves mass analysis with quadrupoles with distorted fields, and may, in the future, allow use of quadrupoles constructed with at least some lower mechanical tolerances.
两个四极滤质器分别带有 4%的附加六极场，采用的是等直径（四极滤质器 4A）和不等直径（四极滤质器 4B）棒，还有一个传统的圆棒四极滤质器，它显然受到了轻微的损坏。通过施加辅助四极激励来形成稳定岛。当马丢参数 a < 0 时，带有六极场的两个四极滤质器正常工作（即没有稳定岛）时，质量分析只能得到低分辨率。使用稳定岛可将分辨率提高 10 倍甚至更多。当 a > 0 时，当四极滤质器 4A 正常工作时，在高于 850 的分辨率下，可以获得类似于传统四极滤质器的峰形。在较低的分辨率下，峰被分裂。当四极滤质器 4B 没有稳定岛时，分辨率可达 2000，但存在低质量尾部和峰上的结构。通过稳定岛的质量分析，两个四极滤质器 4A 和 4B 都显示出没有结构和尾部的峰。在某些工作条件下，离子传输也得到了改善。对于传统的圆棒四极滤质器，使用稳定岛可将极限分辨率从 2500 提高到 4360。在 2500 的分辨率下，传输提高了约两个数量级。这些结果表明，使用稳定岛可以改善具有扭曲场的四极滤质器的质量分析，并且在未来可能允许使用至少具有一些较低机械公差的四极滤质器。
