Heterogeneous samples, particularly those consisting of molecules with masses beyond ~1 MDa, can be challenging to analyze with conventional mass spectrometry instrumentation. With electrospray ionization, the charge states of large ions are typically determined from the spacing of adjacent peaks in the charge-state distribution of a molecule. Heterogeneity in the sample or in the ion population can lead to overlapping charge states that can be difficult or impossible to resolve, an issue that is particularly challenging to overcome for large synthetic polymers or heterogeneous noncovalent complexes of large biomolecules. One solution to this problem of sample heterogeneity for high mass ions is to measure the charge as well of the m/z of individual ions so that the mass of each ion can be determined without interference from other ions. Single ion mass measurements have been done in using a variety of different mass spectrometers, but charge detection mass spectrometry (CDMS) has the advantage that the measurements can be made rapidly and the charge of an ion can be accurately determined from the induced charge in a detector. A new method to measure the energy of an ion while inside the CDMS trap will be presented. This method makes it possible to track energy loss of trapped ion either through fragmentation, solvent evaporation or collisions with background gases. Information that is gained from these measurements will be discussed, and the use of this method for measuring the collisional cross section of an individual ion will be presented.

Mass, mobility and MSN measurements of individual ions with charge detection mass spectrometry

2019 Spring National Meeting

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