Talbert Lance E, Julian Ryan R
Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, CA, 92521, USA.
J Am Soc Mass Spectrom. 2018 Sep;29(9):1760-1767. doi: 10.1007/s13361-018-1934-x. Epub 2018 Apr 5.
Ultraviolet photodissociation or UVPD is an increasingly popular option for tandem-mass spectrometry experiments. UVPD can be carried out at many wavelengths, and it is important to understand how the results will be impacted by this choice. Here, we explore the utility of 213 nm photons for initiating bond-selective fragmentation. It is found that bonds previously determined to be labile at 266 nm, including carbon-iodine and sulfur-sulfur bonds, can also be cleaved with high selectivity at 213 nm. In addition, many carbon-sulfur bonds that are not subject to direct dissociation at 266 nm can be selectively fragmented at 213 nm. This capability can be used to site-specifically create alaninyl radicals that direct backbone dissociation at the radical site, creating diagnostic d-ions. Furthermore, the additional carbon-sulfur bond fragmentation capability leads to signature triplets for fragmentation of disulfide bonds. Absorption of amide bonds can enhance dissociation of nearby labile carbon-sulfur bonds and can be used for stochastic backbone fragmentation typical of UVPD experiments at shorter wavelengths. Several potential applications of the bond-selective fragmentation chemistry observed at 213 nm are discussed. Graphical Abstract ᅟ.
紫外光解离（UVPD）是串联质谱实验中一种越来越受欢迎的选择。UVPD可以在许多波长下进行，了解这种选择如何影响结果很重要。在这里，我们探讨了213纳米光子用于引发键选择性裂解的效用。研究发现，先前确定在266纳米处不稳定的键，包括碳-碘键和硫-硫键，在213纳米处也能以高选择性裂解。此外，许多在266纳米处不会直接解离的碳-硫键在213纳米处可以选择性裂解。这种能力可用于位点特异性地产生丙氨酰基自由基，从而在自由基位点引导主链解离，产生诊断性d离子。此外，额外的碳-硫键裂解能力导致了二硫键裂解的特征性三联体。酰胺键的吸收可以增强附近不稳定碳-硫键的解离，并可用于在较短波长下进行的UVPD实验中典型的随机主链裂解。讨论了在213纳米处观察到的键选择性裂解化学的几种潜在应用。图形摘要ᅟ 。
