Knochenmuss Richard
, Tofwerk AG, 3600, Thun, Switzerland,
J Am Soc Mass Spectrom. 2014 Sep;25(9):1521-7. doi: 10.1007/s13361-014-0931-y. Epub 2014 Jun 10.
Thermal models of ultraviolet MALDI ionization based on the polar fluid concept are re-examined. Key components are very high solvating power of the fluidized matrix and consequent low reaction-free energy, attainment of thermal equilibrium in the fluid, and negligible recombination losses. None of these are found to hold in a MALDI event. The reaction-free energy in the hot matrix must be near the gas phase value, ion formation is too slow to approach equilibrium, and geminate recombination of autoprotolysis pairs greatly increases the initial loss rate. The maximum thermal ion yield is estimated to be many orders of magnitude below experimental values.
基于极性流体概念的紫外基质辅助激光解吸电离（MALDI）热模型被重新审视。关键因素包括流化基质的极高溶剂化能力以及随之而来的低反应自由能、流体中热平衡的达成以及可忽略不计的复合损失。但在MALDI事件中，这些因素均不成立。热基质中的反应自由能必须接近气相值，离子形成速度过慢以至于无法达到平衡，并且自质子解对的双分子复合极大地增加了初始损失率。估计最大热离子产率比实验值低多个数量级。
