Belov M E, Nikolaev E N, Alving K, Smith R D
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA.
Rapid Commun Mass Spectrom. 2001;15(14):1172-80. doi: 10.1002/rcm.356.
External ion accumulation in a two-dimensional (2D) multipole trap has been shown to increase the sensitivity, dynamic range and duty cycle of a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. However, it is important that trapped ions be detected without significant bias at longer accumulation times in the external 2D multipole trap. With increasing ion accumulation time pronounced m/z discrimination was observed when trapping ions in an accumulation quadrupole. In this work we show that superimposing lower rf-amplitude dipolar excitation over the main rf-field in the accumulation quadrupole results in disruption of the m/z discrimination and can potentially be used to achieve unbiased external ion accumulation with FTICR.
二维（2D）多极阱中的外部离子积累已被证明可提高傅里叶变换离子回旋共振（FTICR）质谱仪的灵敏度、动态范围和占空比。然而，重要的是在外部二维多极阱中较长的积累时间内，被捕获的离子能够在无明显偏差的情况下被检测到。在积累四极杆中捕获离子时，随着离子积累时间的增加，观察到明显的质荷比（m/z）歧视现象。在这项工作中，我们表明在积累四极杆的主射频场之上叠加较低射频幅度的偶极激发会导致m/z歧视的破坏，并有可能用于实现FTICR的无偏差外部离子积累。
