Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, USA.
J Am Soc Mass Spectrom. 1996 Dec;7(12):1194-202. doi: 10.1016/S1044-0305(96)00109-2.
Heavy gases (xenon, argon, krypton, methane) have been used to improve the performance of the quadrupole ion trap when performing collision-induced dissociation on peptides. MS/MS spectra reveal that increased amounts of internal energy can be deposited into peptide ions and more structural information can be obtained. Specifically, the pulsed introduction of the heavy gases (as reported previously by Doroshenko, V. M.; Cotter, R. J. Anal. Chem. 1996, 68, 463) provides greater energy deposition without the deleterious effects that static pressures of heavy gas have on spectra. Internal energy deposition as indicated by a qualitative evaluation of MS/MS spectra shows pulsed introduction of heavy gases enables ions to obtain more internal energy than possible by using static pressures of the same heavy gases. A linear correlation is observed between the percentage of heavy gas added and the ratio of product ions used to reflect internal energy deposition. Results here also show that upon pulsed introduction of heavy gases, empirical optimization of a single frequency resonant excitation signal is no longer needed to obtain good MS/MS spectrometry efficiency. The presence of many low mass-to-charge ratio ions and the absence of side chain cleavages in the MS/MS spectra of peptides suggests that the propensity for consecutive fragmentations is increased with the pulsed introduction of heavy gases. In addition, by varying the delay time between introduction of the gas and application of the resonant excitation signal, the amount of fragmentation observed in MS/MS spectra can be changed.
重气体（氙气、氩气、氪气、甲烷）已被用于提高四极离子阱在进行肽碰撞诱导解离时的性能。MS/MS 谱揭示了可以将更多的内部能量沉积到肽离子中，并获得更多的结构信息。具体而言，如 Doroshenko, V. M. 和 Cotter, R. J. 在 1996 年的《分析化学》（Anal. Chem.）杂志中所报道的那样，重气体的脉冲引入提供了更大的能量沉积，而不会像静态重气压那样对光谱产生有害影响。通过对 MS/MS 谱的定性评估，内部能量沉积表明，与使用相同重气压相比，脉冲引入重气体可以使离子获得更多的内部能量。观察到加入重气体的百分比与用于反映内部能量沉积的产物离子的比率之间存在线性相关性。这里的结果还表明，在脉冲引入重气体后，不再需要对单个频率共振激发信号进行经验优化，即可获得良好的 MS/MS 光谱效率。肽的 MS/MS 谱中存在许多低质荷比离子，且没有侧链裂解，这表明随着重气体的脉冲引入，连续碎片化的趋势增加了。此外，通过改变气体引入和共振激发信号施加之间的延迟时间，可以改变 MS/MS 谱中观察到的碎片化程度。
