Differential mobility separation of ions using a rectangular asymmetric waveform
Differential mobility separation of ions using a rectangular asymmetric waveform
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DOI：
10.1021/jp711732c
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发表时间：
2008-04-24
影响因子：
2.9
通讯作者：
Eiceman, G. A.
中科院分区：
文献类型：
--
作者：
Papanastasiou, D.;Wollnik, H.;Eiceman, G. A.
研究了平面差分迁移率谱仪（DMS）在大气压力下工作时的性能，并采用矩形非对称波形驱动，频率< 1.2 MHz，电压脉冲幅度< 1 kV，陡上升时间约为15 ns。频率、电压脉冲幅度和占空比的独立控制允许在传输、分辨率和分离方面表征DMS。实验证明了灵敏度和分辨率之间的权衡以及占空比对仪器性能的影响。离子迁移率对电场大小的依赖性决定了由DC补偿电压测量的离子的位移作为占空比的函数。对于A型和C型离子的分离存在占空比的最佳值，而B型离子表现出更复杂的行为。用于描述占空比对离子分离的影响的分析表达式，确定由补偿电压的变化，开发和比较，在空气中获得的实验结果低于75 Td使用估计的α参数为一组酮。在这种情况下，突出显示了与使用偶次幂多项式计算α参数相关的误差。
The performance of a planar differential mobility spectrometer (DMS) is investigated when operated in air at ambient pressure and driven by a rectangular asymmetric waveform, limited to frequencies of < 1.2 MHz and voltage pulse amplitudes of < 1 kV with steep rise times of the order of similar to 15 ns. Independent control of frequency, voltage pulse amplitude, and duty cycle allow for characterizing the DMS in terms of transmission, resolution and separation. The tradeoff between sensitivity and resolution and the effect of duty cycle on instrument performance are demonstrated experimentally. The dependence of ion mobility on the magnitude of the electric field determines the displacement of ions measured by the DC compensation voltage as a function of the duty cycle. Optimum values for the duty cycle exist for the separation of A- and C-type ions, while, B-type ions exhibit a more complex behavior. An analytical expression for describing the effect of duty cycle on the separation of the ions, determined by variations in the compensation voltage, is developed and compared to experimental results obtained in air below 75 Td using estimated alpha parameters for a set of ketones. In this context, errors associated with the calculation of alpha parameters using polynomials of even powers are highlighted.