Observation of higher order quadrupole excitation frequencies in a linear ion trap
Observation of higher order quadrupole excitation frequencies in a linear ion trap
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DOI：
10.1016/s1044-0305(00)00171-9
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发表时间：
2000-11-01
影响因子：
3.2
通讯作者：
Douglas, DJ
中科院分区：
文献类型：
--
作者：
Collings, BA;Douglas, DJ
测量了Mathieu参数a=0，Q约为0.36的线性四极离子陷阱中受缓冲气体限制的离子的四极激发的共振频率。在没有缓冲气体存在的情况下，预测共振发生在由omega(K)(N)=(omega/K)\n+beta给出的角频率omega(K)(N)处，其中omega是捕获射频的角频率，K=1，2，3…是用微扰理论计算的共振阶数，n=0，+/-1，+/-2，+/-3……通过质子化利血平的碎裂来测量共振。观察到的频率与理论值很接近，但有微小的差异，在K=2时为+0.6%，在K=6时为-2.7%。这可能是共振频率与缓冲气体密度和/或激发幅度有关的结果。当K从1增加到6时，共振的分辨率(从前体的耗尽和碎片离子的形成测量)增加了2倍。这种分辨率的提高需要进一步研究利用高阶共振来隔离和激发囚禁离子。(C)2000年美国质谱学学会。
The resonant frequencies for quadrupole excitation of ions confined with a buffer gas in a linear quadrupole ion trap with Mathieu parameters a = 0 and q approximate to 0.36 have been measured. The resonances are predicted to occur at angular frequencies omega (K)(n) given by omega (K)(n) = (Omega /K)\n + beta\ without the presence of a buffer gas where Omega is the angular frequency of the trapping radio frequency, K = 1, 2, 3... is the order of the resonance calculated with perturbation theory, and n = 0, +/-1, +/-2, +/-3.... The resonances are measured through fragmentation of protonated reserpine. The observed frequencies agree closely with the theoretical values but there are small differences which vary from +0.6% at K = 2 to -2.7% at K = 6. This is believed to be the result of the dependence of the resonant frequencies upon the buffer gas density and/or the excitation amplitude. The resolution of the resonances (measured from the depletion of precursor and formation of fragment ions) increased by a factor of 2 as K increased hom 1 to 6. This increase in resolution warrants further investigation into the use of higher order resonances for isolation and excitation of trapped ions. (C) 2000 American Society for Mass Spectrometry.