Morsa Denis, Hanozin Emeline, Eppe Gauthier, De Pauw Edwin
Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, Liège 4000, Belgium.
J Am Soc Mass Spectrom. 2020 Jun 3;31(6):1167-1171. doi: 10.1021/jasms.0c00108. Epub 2020 May 21.
The fragmentation of benzylpyridinium "thermometer" ions is widely used to quantify the energetics of ions studied by mass spectrometry and other hyphenated techniques such as ion mobility. The reaction pathway leads to a benzylium cation with the release of a neutral pyridine. Using trapped ion mobility spectrometry, we noticed that the addition of acetonitrile, present in the electrosprayed solvent mixture, could occur on some electrophilic benzylium cations. This process results in the formation of adducts and in the appearance of a supplementary mobility peak. We here demonstrate that the addition takes place both in the electrospray source and inside the mobility analyzer, thereby evidencing possible outflow of solvent vapors downstream the instrument. By further characterizing the initial kinetics and the resulting equilibrium linked with the addition reaction, we presently discuss these as alternative probes to calibrate ion temperature in the framework of ion mobility.
苄基吡啶“温度计”离子的碎裂被广泛用于量化通过质谱和其他联用技术（如离子淌度）研究的离子的能量学。该反应途径会生成一个苄基阳离子并释放出中性吡啶。使用捕集离子淌度光谱法时，我们注意到存在于电喷雾溶剂混合物中的乙腈可能会加成到一些亲电苄基阳离子上。这个过程会导致加合物的形成以及出现一个额外的淌度峰。我们在此证明这种加成反应既发生在电喷雾源中，也发生在淌度分析仪内部，从而证明仪器下游可能存在溶剂蒸气流出。通过进一步表征与加成反应相关的初始动力学和最终平衡，我们目前将这些作为在离子淌度框架内校准离子温度的替代探针进行讨论。
