Here we present the implementation of 213-nm ultraviolet photodissociation (UVPD) in a FT-ICR mass spectrometer for chiral differentiation in the gas phase. The L/D amino acid-substituted serine octamer ions were selected as examples of diastereoisomers for chiral analysis. Several kinds of fragment ions were observed in these experiments, including fragment ions that are similar to the ones observed in corresponding collision-activated dissociation (CAD) experiments, fragment ions generated with different protonation sites by only destroying non-covalent bonds, and unique non-covalent cluster radical ions. The latter two kinds of fragment ions are found to be more sensitive to the chirality of the substituted units. Further experiments suggest that the formation of radical ions is mainly affected by chromophores on side chains of the substituted units and micro surroundings of the characterized non-covalent diastereoisomers. A comparing experiment performed by only changing the wavelength of UV laser to 266 nm shows that the 213-nm UV laser has the priority in the diversity of fragmentation pathways and potential of further application in chiral differentiation experiments.

中文翻译：

---

基于213 nm紫外光解离引起的多通道解离的非共价非对映异构体的手性拆分。

在这里，我们介绍了FT-ICR质谱仪中213 nm紫外光解离（UVPD）的实现，用于气相中的手性分化。选择L / D氨基酸取代的丝氨酸八聚体离子作为用于手性分析的非对映异构体的实例。在这些实验中观察到了几种碎片离子，包括与相应的碰撞活化解离（CAD）实验中观察到的碎片离子相似的碎片离子，仅通过破坏非共价键而在不同质子化位点产生的碎片离子以及独特的-共价簇自由基离子。发现后两种碎片离子对取代单元的手性更敏感。进一步的实验表明，自由基离子的形成主要受取代单元侧链上发色团的影响以及特征化非共价非对映异构体的微环境的影响。通过仅将UV激光的波长更改为266 nm进行的比较实验表明，213 nm UV激光在片段化途径的多样性和在手性分化实验中进一步应用的潜力方面具有优先权。