Activation of MALDI plume based on non-dissociative ionization by femtosecond laser fields

本研究的目的是开发一种有效的方法来提高MALDI-MS的灵敏度，该方法基于离子形成机制中的元素反应。我们构建了一个独特的MALDI- tof - ms系统，我们可以引入飞秒（fs）激光脉冲来诱导MALDI目标的解吸，或者电离传统纳秒（ns）紫外激光解吸产生的MALDI羽流中的物质。当聚焦激光脉冲电离DHB基质中苯丙氨酸MALDI羽中的中性物质时，在TOF质谱中检测到分子离子或可识别的大片段离子（Phe+、[Phe- cooh]+、DHB+等）。这意味着利用ns-laser解吸- fs-laser电离的方法可以估计MALDI羽流中离子形成模型中未知的中性物质的数量，对MALDI过程的定量分析有一定的改善作用。

The aim of this research is to develop an effective method which improves MALDI-MS sensitivity based on elementally reactions involved in ion formation mechanism. We constructed a unique MALDI-TOF-MS system to which we can introduce femtosecond(fs) laser pulses to induce desorption of MALDI targets or to ionize species in MALDI plume generated by a conventional nanosecond(ns) UV laser desorption. When neutral species in the MALDI plume of phenylalanine in DHB matrix were ionized by focused fs laser pulses, molecular ions or identifiable large fragment ions (Phe+, [Phe-COOH]+, DHB+,etc.) were detected in the TOF mass spectra. This means that the method using ns-laser desorption followed by fs-laser ionization enables us to estimate amount of neutral species, which has been unknown parameters in the ion formation model in MALDI plume, and will definitely improve the quantitative analysis of MALDI process.