Normandie University, UNIROUEN, INSA Rouen, CNRS, COBRA, 76000 Rouen, France.
CNRS, University of Bordeaux and INSERM, Institut Européen de Chimie et Biologie (IECB, UMS3033, US001), 2 Rue Robert Escarpit, 33600 Pessac, France.
J Am Soc Mass Spectrom. 2020 Apr 1;31(4):969-981. doi: 10.1021/jasms.0c00034. Epub 2020 Mar 10.
In the last years, ion mobility mass spectrometry (IMS-MS) has improved structural analysis and compound identification by giving access to the collision cross section (CCS). An increasingly wide and accurate database of CCS values is now available but often without assessment of the influence of different instrumental settings on CCS values. Here, we present 75 CCS values in helium (CCS) for phosphoric acid cluster anions [(HPO) - H] with charge state () up to 4-. The CCS values, noted CCS, were obtained with a commercial drift tube ion mobility mass spectrometer, in helium, by applying a classic multifield approach. Phosphoric acid clusters are fragile structures that allow to evaluate the effect of different experimental conditions on the retention of weak bonds and their effect on CCS values. We probed harsh and soft voltage gradients in the electrospray (ESI) source before the IMS and two different voltage gradients in the post-IMS region. The variations in the ion mobility and mass spectra consisted in a change in the distribution of the cluster anions aggregation numbers () and charge states (), with a higher amount of multiply charged species for the soft pre-IMS voltage gradient and a lower proportion of cluster dissociation for soft post-IMS conditions. However, the CCS values did not change with experimental conditions for a given cluster, as long as it stays intact from the IMS to the mass analyzer. The CCS were found in good agreement among 3 to 10 replicated values, with a relative standard deviation between 0.1 and 1.7%.
在过去的几年中，离子淌度质谱（IMS-MS）通过提供碰撞截面（CCS），改善了结构分析和化合物鉴定。现在，CCS 值的数据库越来越广泛和准确，但通常没有评估不同仪器设置对 CCS 值的影响。在这里，我们提出了 75 个在氦气中（CCS）的磷酸酸簇负离子 [(HPO) - H]的 CCS 值，其电荷态 () 高达 4-。CCS 值，记为 CCS，是在氦气中使用商业漂移管离子淌度质谱仪，通过应用经典的多场方法获得的。磷酸酸簇是脆弱的结构，允许评估不同实验条件对弱键保留的影响及其对 CCS 值的影响。我们在 IMS 之前的电喷雾（ESI）源中探测了苛刻和柔和的电压梯度，以及 IMS 后区域中的两个不同的电压梯度。离子淌度和质谱的变化包括簇负离子聚合数 () 和电荷态 () 的分布变化，对于柔和的 IMS 前电压梯度，多电荷物种的数量增加，而对于柔和的 IMS 后条件，簇解离的比例降低。然而，只要给定的簇在 IMS 到质量分析仪之间保持完整，CCS 值就不会随实验条件而变化。CCS 值在 3 到 10 个重复值之间具有良好的一致性，相对标准偏差在 0.1 到 1.7%之间。
