Simple fitting of energy-resolved reactive cross sections in threshold collision-induced dissociation (T-CID) experiments
Simple fitting of energy-resolved reactive cross sections in threshold collision-induced dissociation (T-CID) experiments
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DOI：
10.1021/jp072092l
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发表时间：
2007-08-02
影响因子：
2.9
通讯作者：
Chen, Peter
中科院分区：
文献类型：
--
作者：
Narancic, Sanja;Bach, Andreas;Chen, Peter
提出了一种操作上简单得多的方法，用于从能量分辨碰撞诱导解离截面中提取热化学数据，该截面是专门为通过串联质谱测定配体结合能而设计的。与文献中已有的方法相比，本方法具有三个优点：（i）对离子与碰撞伙伴接近的静电势进行更现实的处理，从而产生更好的非经验阈值函数，允许在整个能量范围内拟合截面，而不仅仅是开始。(ii)治疗的动力学位移与一个新的模型的状态密度函数消除了需要明确输入的起始离子或过渡态的频率，而不损失的准确性相对于直接的状态计数。(iii)数据拟合使用Monte Carlo模拟和遗传算法，而不是通常的Marquardt-Levenburg最小二乘例程不仅产生了等效的拟合，但也产生了统计相关的误差界上导出的拟合参数。虽然该方法被认为是中型到大型的有机金属配合物，该理论是普遍的，足以适用于广泛的结合现象的小分子到一个较大的质谱观察。
An operationally much simpler method for the extraction of thermochemical data from energy-resolved collision-induced dissociation cross sections, which is specifically designed for ligand binding energy determinations by tandem mass spectrometry, is presented. Compared to previous methods available in the literature, the present method has three advantages: (i) A more realistic treatment of the electrostatic potential for the approach of the ion to the collision partner leads to a better, nonempirical threshold function, allowing fitting of the cross section over the entire energy range rather than just the onset. (ii) Treatment of the kinetic shift with a new model for the density-of-states function eliminates the need for explicit entry of frequencies for the starting ion or the transition state without loss of accuracy relative to direct state counts. (iii) Data fitting using Monte Carlo simulation and a genetic algorithm instead of the usual Marquardt-Levenburg least-squares routines not only produces an equivalent fit but also produces statistically relevant error bounds on the derived fit parameters. Although the method is conceived for medium-to-large organometallic complexes, the theory is general enough to be appropriate for a wide range of binding phenomena of a small molecule to a larger one observed in mass spectrometry.