Knochenmuss Richard
Novartis Institutes for Biomedical Research, WSJ 503.1104, 4052 Basel, Switzerland.
Eur J Mass Spectrom (Chichester). 2009;15(2):189-98. doi: 10.1255/ejms.960.
Laser desorption/ionization from structured surfaces has been the object of recently renewed interest. Conditions in the plume of material ablated from such surfaces may differ from those of a sample which is ablated in bulk. Since recombination and secondary ion-molecule reactions in the plume play a major role in determining the types and quantities of ions observed at the detector, these differences are analytically relevant. Desorption/ionization substrates with channels of high aspect ratio are modeled as capillary nozzles, from which free jets are emitted. A previously developed matrix-assisted laser desorption/ionization ablation/ionization model is adapted for these jets. More primary ions reach the detector when ablated from a capillary orifice, but fewer analye ions are created in secondary reactions. These differences in ion yield can persist for arrays of capillaries on the surface, depending on the ratio of their diameter to spacing.
来自结构化表面的激光解吸/电离一直是近期重新受到关注的对象。从此类表面烧蚀的物质羽流中的条件可能与整体烧蚀的样品不同。由于羽流中的复合和二次离子 - 分子反应在确定探测器处观察到的离子类型和数量方面起主要作用，这些差异在分析上具有相关性。具有高纵横比通道的解吸/电离基底被建模为毛细管喷嘴，从中发射自由射流。先前开发的基质辅助激光解吸/电离烧蚀/电离模型适用于这些射流。从毛细管孔口烧蚀时，更多的初级离子到达探测器，但在二次反应中产生的分析物离子较少。取决于其直径与间距的比率，这些离子产率的差异可能在表面上的毛细管阵列中持续存在。
