Peris-Díaz Manuel D, Barendregt Arjan, Wörner Tobias P, Fort Kyle L, Makarov Alexander A, Deslignière Evolène, Heck Albert J R
Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht 3584 CH, the Netherlands.
Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Wrocław 50-383, Poland.
Anal Chem. 2025 Jun 10;97(22):11653-11660. doi: 10.1021/acs.analchem.5c01000. Epub 2025 May 28.
Recently, the use of ultralong transients has enabled exceptional resolution and sensitivity in Orbitrap-based charge detection mass spectrometry (CDMS). Nevertheless, measuring small analytes carrying a few charges remains a challenge. Prolonged trapping should, in theory, allow for the detection of lower charged ions (<10+) due to enhanced signal-to-noise (/) ratios. However, in practice, due to ion decay through frequency drifts, or collision-induced fragmentations, low / ions deviate from the ideal coherent trajectories in the Orbitrap. Here, by incorporating electron capture charge reduction (ECCR) in the gas phase prior to CDMS, we show that charge reduction significantly improves the stability of ion trajectories when ions are trapped for long periods in the Orbitrap analyzer. Using proteins with molecular weights ranging from 12 to 900 kDa, we demonstrate that ECCR-CDMS enhances ion survival by up to 60-fold, even enabling the detection of doubly charged individual ions from cytochrome c that typically elude conventional Orbitrap-based CDMS.
最近，超长瞬态的使用在基于轨道阱的电荷检测质谱（CDMS）中实现了卓越的分辨率和灵敏度。然而，测量携带少量电荷的小分子分析物仍然是一个挑战。从理论上讲，延长捕获时间应该能够检测到由于信噪比提高而带电量更低的离子（<10 +）。然而，在实际操作中，由于离子通过频率漂移或碰撞诱导碎片化而衰减，低/离子会偏离轨道阱中理想的相干轨迹。在这里，通过在CDMS之前在气相中引入电子捕获电荷减少（ECCR），我们表明当离子在轨道阱分析仪中长时间捕获时，电荷减少显著提高了离子轨迹的稳定性。使用分子量范围为12至900 kDa的蛋白质，我们证明ECCR-CDMS可将离子存活率提高多达60倍，甚至能够检测到细胞色素c中通常无法通过传统基于轨道阱的CDMS检测到的双电荷单个离子。
