Department of Chemistry, University of California, Berkeley, California 94720, United States.
J Am Soc Mass Spectrom. 2022 Mar 2;33(3):607-611. doi: 10.1021/jasms.1c00372. Epub 2022 Feb 14.
Nanoelectrospray ionization emitters with submicron tip diameters have significant advantages for use in native mass spectrometry, including the ability to produce resolved charge-state distributions for proteins and macromolecular complexes from standard biochemical buffers that contain high concentrations of nonvolatile salts and to prevent nonspecific aggregation that can occur during droplet evaporation. We report on various factors affecting the tip morphology and provide suggestions for producing and using emitters with submicron tips. Effects of pulling parameters for a Sutter Instrument P-87 tip puller on the resulting tip diameter and morphology are shown. The "Pull" parameter has the largest effect on tip diameter, followed by "Velocity", "Pressure", and "Heat", whereas the "Time" parameter has minimal effect beyond a lower threshold. High "Pull" values generate emitters with multiple tapers, whereas high "Velocity" values generate a tip with only a single tapered region. A protocol for producing reproducible emitters in the submicron size range, as well as guidelines and tips for using these emitters with standard biochemical buffers that contain high concentrations of nonvolatile salts, is presented with the aim of expanding their use within the native mass spectrometry community.
具有亚微米尖端直径的纳升电喷雾发射器在天然质谱学中具有显著优势，包括能够在标准生化缓冲液中产生分辨率较高的电荷态分布，这些缓冲液中含有高浓度的不可挥发盐，并且可以防止在液滴蒸发过程中发生非特异性聚集。我们报告了影响尖端形态的各种因素，并提供了生产和使用亚微米尖端发射器的建议。显示了对 Sutter Instrument P-87 尖端拉拔器的各种拉出参数对最终尖端直径和形态的影响。“拉”参数对尖端直径的影响最大，其次是“速度”、“压力”和“加热”，而“时间”参数在低于下限阈值后影响最小。高“拉”值会产生具有多个锥度的发射器，而高“速度”值只会产生具有单个锥形区域的尖端。提出了一种在亚微米尺寸范围内生产可重复的发射器的方案，以及在含有高浓度不可挥发盐的标准生化缓冲液中使用这些发射器的指南和技巧，目的是在天然质谱学领域扩大它们的使用。
