Theory of operation for differential ion mobility spectrometry without alpha
Theory of operation for differential ion mobility spectrometry without alpha
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DOI：
10.1007/s12127-012-0104-2
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发表时间：
2012-06
影响因子：
--
通讯作者：
G. Spangler
中科院分区：
文献类型：
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作者：
G. Spangler
使用Langevin方程的离子运动在一个可变的电场的存在下，并表示的碰撞频率的方式，符合散射的多原子离子与等效硬球核心，一个关系推导出的补偿和色散场的差分离子迁移谱仪（DIMS）。对于保守碰撞（没有成簇或离子中性解离或重排相互作用），补偿场取决于色散场的偶次幂和奇次幂，并且当场除以漂移气体密度时，两个场之间的关系与压力无关。因为补偿场的第一和最重要的近似与零场条件下离子迁移率的平方成比例，所以补偿场随着漂移气体的温度而增加，但是温度依赖性的函数形式涉及更高阶项，并且需要碰撞截面的温度依赖性的附加知识。长链仲酮的占空比曲线与使用非对称矩形波形进行激励的实验相比是有利的。
Using the Langevin equation for ion motion in the presence of a variable electric field, and expressing the collision frequency in a manner that conforms to scattering a polyatomic ion with an equivalent hard-sphere core, a relationship is derived for the compensation and dispersion fields in a differential ion mobility spectrometer (DIMS). For a conservative collision (no clustering or ion-neutral dissociation or rearrangement interactions), the compensation field depends on both even and odd powers of the dispersion field, and the relationship between both fields is independent of pressure when the fields are divided by the drift gas density. Because the first and most important approximation for the compensation field is proportional to the square of ion mobility under zero field conditions, the compensation field increases with the temperature of the drift gas, but the functional form for the temperature dependence involves higher order terms and requires additional knowledge of the temperature dependence for the collision cross section. Duty cycle curves for long-chain secondary ketones compare favorably to experiments using an asymmetric rectangular waveform for excitation.