Brabeck Gregory F, Chen Huijuan, Hoffman Nathan M, Wang Liang, Reilly Peter T A
Department of Chemistry, Washington State University , Fulmer 305, Pullman, Washington 99164, United States.
Anal Chem. 2014 Aug 5;86(15):7757-63. doi: 10.1021/ac501685v. Epub 2014 Jul 8.
This publication demonstrates the use of digital waveform manipulation in linear ion guides to trap isolated ions and fragment them before mass analysis by time-of-flight mass spectrometry (TOF-MS). Ion trapping and collection was performed by waveform duty cycle manipulation to create a negative axial potential between the rods and the end-cap electrodes. Ion isolation can be performed by duty cycle manipulation to narrow the range of stable masses while continuing to axially trap the ions. Further ion isolation can then be performed by jumping the quadrupole frequency to each side of the stability zone to eliminate ions above and below the isolated ion mass. Collision-induced dissociation was demonstrated by duty cycle manipulation to either axially or radially excite the ions. The methods for performing these types of excitations are discussed and demonstrated. These techniques can be combined or used separately for MS(n) analysis. The use of frequency and duty cycle manipulation of the applied waveforms simplifies the hardware while greatly increasing the capabilities of linear ion guides and quadrupole time-of-flight mass spectrometers (Q-TOF-MS). Linear quadrupoles can now be used as high efficiency ion traps for collection, isolation, and tandem mass spectrometry at any value of m/z when operated digitally.
本出版物展示了在线性离子阱中使用数字波形操纵来捕获孤立离子，并在通过飞行时间质谱（TOF-MS）进行质量分析之前使其碎片化。离子捕获和收集通过波形占空比操纵来实现，以在杆和端盖电极之间产生负轴向电位。离子隔离可通过占空比操纵来进行，以缩小稳定质量范围，同时继续轴向捕获离子。然后可以通过将四极杆频率跳转到稳定区的每一侧来进一步隔离离子，以消除隔离离子质量以上和以下的离子。碰撞诱导解离通过占空比操纵来证明，以轴向或径向激发离子。讨论并展示了执行这些类型激发的方法。这些技术可以组合使用或单独用于MS(n)分析。应用波形的频率和占空比操纵的使用简化了硬件，同时大大提高了线性离子阱和四极杆飞行时间质谱仪（Q-TOF-MS）的功能。当以数字方式操作时，线性四极杆现在可以用作高效离子阱，用于在任何m/z值下进行收集、隔离和串联质谱分析。
