Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
J Am Soc Mass Spectrom. 2011 Feb;22(2):369-78. doi: 10.1007/s13361-010-0027-2. Epub 2011 Jan 15.
The halo ion trap (IT) was modified to allow for axial ion ejection through slits machined in the ceramic electrode plates rather than ejecting ions radially to a center hole in the plates. This was done to preserve a more uniform electric field for ion analysis. An in-depth evaluation of the higher-order electric field components in the trap was also performed to improve resolution. The linear, cubic and quintic (5th order) electric field components for each electrode ring inside the IT were calculated using SIMION (SIMION version 8, Scientific Instrument Services, Ringoes, NJ, USA) simulations. The preferred electric fields with higher-order components were implemented experimentally by first calculating the potential on each electrode ring of the halo IT and then soldering appropriate capacitors between rings without changing the original trapping plate design. The performance of the halo IT was evaluated for 1% to 7% cubic electric field (A (4)/A (2)) component. A best resolution of 280 (m/Δm) for the 51-Da fragment ion of benzene was observed with 5% cubic electric field component. Confirming results were obtained using toluene, dichloromethane, and heptane as test analytes.
晕圈离子阱（IT）经过改造，允许通过在陶瓷电极板上加工的狭缝进行轴向离子喷射，而不是将离子径向喷射到板中心的孔中。这样做是为了保持更均匀的电场以进行离子分析。还对陷阱中的高阶电场分量进行了深入评估，以提高分辨率。使用 SIMION（SIMION 版本 8，Scientific Instrument Services，Ringoes，NJ，USA）模拟计算了 IT 内每个电极环的线性、立方和五次（五阶）电场分量。通过首先计算晕圈 IT 每个电极环上的电势，然后在不改变原始捕获板设计的情况下在环之间焊接适当的电容器，在实验中实现了具有更高阶分量的优选电场。评估了晕圈 IT 在 1%到 7%立方电场（A (4)/A (2))分量下的性能。当立方电场分量为 5%时，苯的 51-Da 片段离子的最佳分辨率为 280（m/Δm）。使用甲苯、二氯甲烷和正庚烷作为测试分析物得到了确认结果。
