Image charge detection mass spectrometry: pushing the envelope with sensitivity and accuracy.
Image charge detection mass spectrometry: pushing the envelope with sensitivity and accuracy.
复制标题
图像电荷检测质谱：以灵敏度和准确性突破极限。
作者：
John W. Smith;Elizabeth E Siegel;Joshua T. Maze;M. Jarrold
描述了一种具有改进的灵敏度和质量准确度的新型图像电荷检测质谱仪（CDMS）。改进的探测器设计和数据分析方法使我们能够测量单个宏离子的可靠质量，该质量比以前使用 CDMS 实现的质量小一个数量级。该装置采用由22个探测器组成的图像电荷探测器阵列。探测器分为两组，可以浮动在不同的电位。使用相关方法分析来自探测器阵列的信号，以得出两组探测器和电荷的速度。这些量与两组探测器之间的电压差一起提供了质量值。显示了 300 kDa 聚环氧乙烷 (PEG) 记录的质量、m/z 和电荷分布。质量分布显示在 300 kDa 左右有一个峰值，其宽度接近聚合物尺寸分布的预期宽度。此外，质量分布在 100 和 500 MDa 左右存在宽峰。 300 kDa 离子的 m/z 比为 ∼2 kDa/e，100 和 500 MDa 离子的 m/z 比为 ∼40 kDa/e。 100 和 500 MDa 离子可能是由 PEG 聚集体产生的，这些聚集体要么存在于溶液中，要么存在于大电喷雾液滴的残留物中。
A novel image charge detection mass spectrometer (CDMS) with improved sensitivity and mass accuracy is described. The improved detector design and method of data analysis allow us to measure a reliable mass for a single macroion that is an order of magnitude smaller than previously achieved with CDMS. The apparatus employs an image charge detector array consisting of 22 detectors. The detectors are divided into two groups that can be floated at different potentials. The signals from the detector array are analyzed using a correlation approach to yield the velocities in the two groups of detectors and the charge. These quantities, together with the voltage difference between the two groups of detectors, provide a value for the mass. The mass, m/z, and charge distributions recorded for 300 kDa poly(ethylene oxide) (PEG) are presented. The mass distribution shows a peak at around 300 kDa with a width close to that expected from the polymer size distribution. In addition, there are broad peaks in the mass distribution at around 100 and 500 MDa. The 300 kDa ions have m/z ratios of ∼2 kDa/e, and the 100 and 500 MDa ions have m/z ratios of ∼40 kDa/e. The 100 and 500 MDa ions probably result from PEG aggregates that are either present in solution or the residue of large electrospray droplets.