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Electrospray ionization interface to high pressure mass spectrometry and related methods

專利號
US10867781B2
公開日期
2020-12-15
申請人
The University of North Carolina at Chapel Hill（US NC Chapel Hill）
發(fā)明人
John Michael Ramsey; William McKay Gilliland, Jr.
IPC分類
H01J49/16; H01J49/24; H01J49/00; H01J49/04; B01L3/00
技術領域
mass,esi,analyzer,about,mm,inlet,chamber,ion,vacuum,trap
地域： NC NC Chapel Hill

摘要

An electrospray ionization (ESI)-mass spectrometer analysis systems include an ESI device with at least one emitter configured to electrospray ions and a mass spectrometer in fluid communication with the at least one emitter of the ESI device. The mass spectrometer includes a mass analyzer held in a vacuum chamber. The vacuum chamber is configured to have a high (background/gas) pressure of about 50 mTorr or greater during operation. During operation, the ESI device is configured to either; (a) electrospray ions into a spatial region external to the vacuum chamber and at atmospheric pressure, the spatial extent being adjacent to an inlet device attached to the vacuum chamber, the inlet device intakes the electrosprayed ions external to the vacuum chamber with the mass analyzer and discharges the ions into the vacuum chamber with the mass analyzer; or (b) electrospray ions directly into the vacuum chamber with the mass analyzer.

說明書

FIG. 20 is a diagram illustrating high pressure ion trap theory with operational parameters. Importantly, the resolving power of an ion trap mass spectrometer is proportional to the RF drive frequency, Ω, divided by the operating pressure, P. Thus, resolution can be recovered when P is increased by correspondingly increasing Ω. FIG. 20 also shows that the magnitude of χ required for ion ejection is inversely related to trap dimensions, r0 and z0. FIG. 21 is a graph showing experimental results for mass spectral resolution when using different RF frequencies and r0 sizes in normalized intensity (A.U.) Resolution changes according to ion trap theory shown in FIG. 20.

In summary, a microchip electrospray ionization source can be successfully coupled to a high pressure mass spectrometer and can use an ambient, e.g, atmospheric) pressure inlet of a metallic, e.g., stainless steel, capillary and DC ion control to conduct ions into the mass spectrometer. Infusions of amino acids and peptides were performed and detected with a miniature cylindrical ion trap (mini-CIT) based mass spectrometer operated at ≥1 Torr with air as the buffer gas. Detection of thymopentin demonstrated the mass range of the mini-CIT detector could be extended to at least 681 m/z. Small proteins have also been observed using systems as described above, e.g., cytochrome C and myoglobin with masses of approximately 12 k Da and 17 k Da, respectively.

權利要求

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