Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization
Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization
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DOI：
10.1002/jms.1732
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发表时间：
2010-04-01
影响因子：
2.3
通讯作者：
Zhigilei, Leonid V.
中科院分区：
文献类型：
--
作者：
Knochenmuss, Richard;Zhigilei, Leonid V.
用分子动力学方法模拟了基质辅助激光解吸/电离过程，研究了激光脉冲宽度和注量对一次电离和二次电离过程的影响。在相同的通量下，短脉冲(35或350 ps)会导致比长脉冲(3 Ns)高得多的初始压力和离子浓度，但这些差异并不持久，因为系统在纳秒时间尺度上向局部热平衡松弛。较高的流量会加剧初始差异，但下游差异并不显著。发现离子和中性粒子的轴向速度跨越很大的范围，并且与通量有关。总离子产额仅与脉冲宽度有微弱的依赖关系，并与实验估计一致。即使分析物离子在基质簇中被烧蚀，基质阳离子与分析物中性物质的二次反应也是有效的。版权所有(C)2010 John Wiley&Sons，Ltd.
Molecular dynamics simulations of matrix-assisted laser desorption/ionization were carried out to investigate laser pulse width and fluence effects on primary and secondary ionization process. At the same fluence, short (35 or 350 ps) pulses lead to much higher initial pressures and ion concentrations than longer ones (3 ns), but these differences do not persist because the system relaxes toward local thermal equilibrium on a nanosecond timescale. Higher fluences accentuate the initial disparities, but downstream differences are not substantial. Axial velocities of ions and neutrals are found to span a wide range, and be fluence dependent. Total ion yield is only weakly dependent on pulse width, and consistent with experimental estimates. Secondary reactions of matrix cations with analyte neutrals are efficient even though analyte ions are ablated in clusters of matrix. Copyright (C) 2010 John Wiley & Sons, Ltd.