Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
J Am Soc Mass Spectrom. 2017 Sep;28(9):1929-1938. doi: 10.1007/s13361-017-1707-y. Epub 2017 Jun 2.
Reported herein is a simple method of performing single analyzer precursor ion scans in a linear quadrupole ion trap using orthogonal double resonance excitation. A first supplementary AC signal applied to the y electrodes is scanned through ion secular frequencies in order to mass-selectively excite precursor ions while, simultaneously, a second fixed-frequency AC signal is applied orthogonally on the x electrodes in order to eject product ions of selected mass-to-charge ratios towards the detector. The two AC signals are applied orthogonally so as to preclude the possibility of (1) inadvertently ejecting precursor ions into the detector, which results in artifact peaks, and (2) prevent beat frequencies on the x electrodes from ejecting ions off-resonance. Precursor ion scans are implemented while using the inverse Mathieu q scan for easier mass calibration. The orthogonal double resonance experiment results in single ion trap precursor scans with far less intense artifact peaks than when both AC signals are applied to the same electrodes, paving the way for implementation of neutral loss scanning in single ion trap mass spectrometers. Graphical Abstract ᅟ.
本文报道了一种在线性四极离子阱中使用正交双共振激发进行单分析器前体离子扫描的简单方法。施加到 y 电极的第一辅助交流电信号通过离子 secular 频率进行扫描，以便选择性地激发前体离子，同时，第二固定频率交流电信号正交施加在 x 电极上，以便将选定质荷比的产物离子朝向检测器喷射。这两个交流电信号正交施加，以排除以下两种可能性：（1）无意中将前体离子喷射到检测器中，从而产生伪峰；（2）防止 x 电极上的拍频将离子逐出离谐。在前体离子扫描过程中，使用逆 Mathieu q 扫描进行质量校准，以实现更容易的质量校准。正交双共振实验产生的单离子阱前体扫描的伪峰强度远低于两个交流电信号施加到相同电极时的强度，为在单离子阱质谱仪中实现中性丢失扫描铺平了道路。图摘要。
