Electrospray ionization interface to high pressure mass spectrometry and related methods
摘要
說明書
The electrode apertures 31, 32, 33 each have a radius r0 or average effective radius (e.g., the latter calculates an average hole size using shape and width/height dimensions where non-circular aperture shapes are used) and the trap 30 has a corresponding diameter or average cross distance 2r0 and an effective length 2z0. The ion trap 30 can be configured to have a defined ratio of z0/r0 that is greater than 0.83. Note that z0 can be defined as the half-height of the cavity. In some embodiments, the ion trap aperture array has an effective length 2z0 measured as the distance between interior surfaces of the end caps 31, 32. The array can be configured to have a defined ratio of z0/r0 that is near unity but is generally greater than unity by about 10% to about 30%. The r0 and z0 dimensions can be between about 0.5 μm to about 1 cm, but for microscale mass spectrometry applications contemplated by certain embodiments of the invention, these dimensions are preferably 1 mm or less, down to about 0.5 μm. The mass analyzer 30 can be an ion trap with three stacked (metal) electrodes 31, 32, 33 separated by insulators. For further discussion of exemplary CIT configurations, see U.S. Pat. Nos. 6,933,498, and 6,469,298, the contents of which are hereby incorporated by reference as if recited in full herein. An example of a single electrode ionizer is described in Kornienko, Anal. Chem. 2000, 72, 559-562 and Kornienko, Rapid Commun. Mass Spectrom. 1999, 13, 50-53, the contents of which are hereby incorporated by reference as if recited in full herein.
The distance “d” is typically chosen such that z0 is slightly larger than r0, typically 10-30% larger.
