Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche, Università degli Studi di Palermo, V.le delle Scienze-Ed, 16-90128, Palermo, Italy.
J Mass Spectrom. 2013 Mar;48(3):379-83. doi: 10.1002/jms.3161.
The characteristic collision energy (CCE) to obtain 50% fragmentation of positively and negatively single charged noncovalent clusters has been measured. CCE was found to increase linearly with the degrees of freedom (DoF) of the precursor ion, analogously to that observed for synthetic polymers. This suggests that fragmentation behavior (e.g. energy randomization) in covalent molecules and clusters are similar. Analysis of the slope of CCE with molecular size (DoF) indicates that activation energy of fragmentation of these clusters (loss of a monomer unit) is similar to that of the lowest energy fragmentation of protonated leucine-enkephalin. Positively and negatively charged aggregates behave similarly, but the slope of the CCE versus DoF plot is steeper for positive ions, suggesting that these are more stable than their negative counterparts.
已测量得到使正、负离子非共价单电荷簇分别碎裂 50%的特征碰撞能 (CCE)。与合成聚合物类似，CCE 被发现随前体离子自由度 (DoF)呈线性增加。这表明共价分子和簇的碎裂行为（例如能量随机化）相似。对 CCE 与分子大小（DoF）的斜率进行分析表明，这些簇的碎裂活化能（损失一个单体单元）与亮氨酸脑啡肽质子化后最低能量碎裂的活化能相似。正、负离子聚集体的行为相似，但 CCE 与 DoF 关系图的斜率对于正离子更陡峭，这表明它们比负离子更稳定。
