Thermal dissociation of gaseous bradykinin ions
Thermal dissociation of gaseous bradykinin ions
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DOI：
10.1021/jp9924979
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发表时间：
1999-10-28
影响因子：
2.9
通讯作者：
McLuckey, SA
中科院分区：
文献类型：
--
作者：
Butcher, DJ;Asano, KG;McLuckey, SA
单、双、三带电荷的缓激肽离子在四极离子阱中被热解离，该离子阱主要由1mtorr的氦气组成。利用产物离子谱测定了解离率与浴气温度的关系。研究表明，解离速率与离子储存条件和浴气压力无关。这些研究表明，使用浴气温度作为母离子群内能分布的度量，可以从阿伦尼乌斯图中很好地近似确定真实的阿伦尼乌斯参数，本工作中得到的阿伦尼乌斯参数与最近报道的使用黑体诱导辐射解离对单带电和双带电离子在实验误差范围内的结果一致。解离产物的光谱也非常相似，反映了两种方法推导阿伦尼乌斯参数的等效性。本文首次报道了三电荷离子（E-a= 0.79 +/- 0.03 eV; log A = 9.3 +/- 0.36 s(-1)）的Arrhenius参数。通过对双亲离子和三双亲离子的阿伦尼乌斯参数的比较，以及两双亲离子失水形成离子的解离反应表明，双质子化缓激肽和三质子化缓激肽的失水反应是通过明显不同的机制进行的。
Singly, doubly, and triply charged bradykinin ions have been dissociated thermally in a quadrupole ion trap operated with a bath gas comprised principally of helium at 1 mTorr. Dissociation rates as a function of bath gas temperature were measured along with product ion spectra. Studies were conducted to show that dissociation rates were independent of ion storage conditions and bath gas pressure. These studies indicate that good approximations to true Arrhenius parameters could be determined from Arrhenius plots using the bath gas temperature as a measure of the internal energy distribution of the parent ion population, Arrhenius parameters derived in this work agree with those reported recently using blackbody-induced radiative dissociation for the singly and doubly charged ions within experimental error. The spectrum of dissociation products were also very similar, reflecting the equivalency of the two methods for deriving Arrhenius parameters. Arrhenius parameters for the triply charged ion (E-a= 0.79 +/- 0.03 eV; log A = 9.3 +/- 0.36 s(-1)) are reported for the first time. Comparison of the Arrhenius parameters for the doubly and triply charged parent ions, along with dissociation reactions of the ions formed via water loss from the two parent ions indicate that water loss reactions from doubly protonated bradykinin and from triply protonated bradykinin proceed via distinctly different mechanisms.