Mapping the Distribution of Ion Positions as a Function of Quadrupole Ion Trap Mass Spectrometer Operating Parameters to Optimize Infrared Multiphoton Dissociation
Mapping the Distribution of Ion Positions as a Function of Quadrupole Ion Trap Mass Spectrometer Operating Parameters to Optimize Infrared Multiphoton Dissociation
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DOI：
10.1021/jp808955w
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发表时间：
2009-04-16
影响因子：
2.9
通讯作者：
Glish, Gary L.
中科院分区：
文献类型：
--
作者：
Remes, Philip M.;Glish, Gary L.
红外多光子解离（IRMPD）结合离子轨迹模拟已被用于在四极离子阱质谱仪中获取离子位置随不同操作参数变化的概率图。对影响伪势阱深度的因素进行了分析，并展示了它们对IRMPD效率的影响。离子轨迹模拟被用于证实实验结果，并更详细地展示离子群位置分布的动态特性。特别地，研究表明在光解离过程中使用的所谓“q(z)值”以及施加在环形电极上的交流俘获电压的频率都可能具有重大影响。结果显示，增加伪势阱的参数具有减小离子云尺寸以及使照射激光和离子之间的重叠最大化的效果。因此，尽管对IRMPD的普遍理解并非如此，但IRMPD的裂解效率实际上取决于许多离子阱操作参数，这与碰撞诱导解离很相似。
Infrared multiphoton dissociation (IRMPD) combined with ion trajectory simulations has been used to obtain probability maps of ion position as a function of different operating parameters in a quadrupole ion trap mass spectrometer. The factors that contribute to the depth of the pseudopotential trapping well are analyzed, and their effects on the efficiency of IRMPD are demonstrated. Ion trajectory simulations are used to substantiate experimental results and demonstrate in greater detail the dynamic nature of the ion population's positional distribution. In particular, it is shown that the so-called "q(z) value" used during photodissociation can be of great consequence, as can the frequency of ac trapping voltage applied to the ring electrode. The results reveal that parameters which increase the pseudopotential well have the effect of decreasing the size of the ion cloud and maximizing overlap between the irradiating laser and the ions. Thus, while the common understanding of IRMPD dictates otherwise, IRMPD fragmentation efficiencies really depend on many ion trap operating parameters, much as collision-induced dissociation does.