Belov M E, Gorshkov M V, 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(21):1988-96. doi: 10.1002/rcm.459.
When combined with on-line separations (e.g., capillary liquid chromatography (LC)), Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) provides a powerful tool for biological applications, and particularly proteomic studies. The sensitivity, dynamic range, and duty cycle provided by FTICR-MS have been shown to be increased by ion trapping and accumulation in a two-dimensional (2D) radio-frequency (rf)-only multipole positioned externally to an FTICR cell. However, it is important that ions be detected across the desired m/z range without a significant bias. In this work we found that pressure inside the accumulation rf-quadrupole plays an important role in obtaining "unbiased" ion accumulation. Pressure optimization was performed in both pulsed and continuous modes. It was found that unbiased accumulation in a 2D rf-only quadrupole could be achieved in the pressure range of 5 x 10(-4) to 5 x 10(-3) Torr. External ion accumulation performed at the optimal pressure resulted in an increase in both the spectrum acquisition rates and dynamic range.
傅里叶变换离子回旋共振质谱（FTICR-MS）与在线分离技术（如毛细管液相色谱（LC））相结合时，可为生物学应用，尤其是蛋白质组学研究提供强大工具。FTICR-MS的灵敏度、动态范围和工作周期可通过在FTICR池外部的二维（2D）仅射频（rf）多极中进行离子捕获和积累来提高。然而，重要的是要在所需的质荷比范围内无明显偏差地检测离子。在这项工作中，我们发现积累射频四极杆内部的压力在实现“无偏差”离子积累方面起着重要作用。在脉冲模式和连续模式下都进行了压力优化。结果发现，在5×10⁻⁴至5×10⁻³托的压力范围内，可在二维仅射频四极杆中实现无偏差积累。在最佳压力下进行外部离子积累可提高光谱采集速率和动态范围。
