Mass spectrometry (MS) is an analytical technique that measures the mass-to-charge ratio of charged particles. It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and other chemical compounds. The MS principle consists of ionizing chemical compounds to generate charged molecules or molecule fragments and measurement of their mass-to-charge ratios.
In a typical MS procedure, a sample is loaded onto the MS instrument and undergoes vaporization. The components of the sample are ionized by one of a variety of methods (e.g., by impacting them with an electron beam), which results in the formation of charged particles (ions). The ions are separated according to their mass-to-charge ratio in a mass analyzer by electromagnetic fields. The ions are detected, usually by a quantitative method. The ion signal is processed into mass spectra.
Ion storage devices that use RF fields for transporting or storing ions have become standard in mass spectrometers. One ion guide is the humpbacked ion guide, shown in
In one embodiment, a mass spectrometry system arrangement that includes a bent ion guide, where the bend of the ion guide is positioned such that a portion of the ion optics are visible from at the ion guide entrance, e.g. line of sight or longitudinal axis. There are four electrodes parallel with each other and the central curved axis. Each electrode is equally radially spaced from the curved central axis. For each cross section of the ion guide, the central curved axis being positioned at the origin, the curved electrodes being radially positioned at 45°, 135°, 225°, and 315°.
A removable blocking device is positioned external to the ion guide but within the “line of sight” of the ion optics.
The removable blocking device is a physical barrier large enough to collect the debris that could reenter the ion guide and accumulate on the ion optics or generate spikes.
In another embodiment, a mass spectrometry system that includes an alternate bent ion guide. The gas stream moves tangentially along a portion of the ion guide. The removable blocking device is positioned external to the ion guide.
The bend of the ion guide 12 is positioned such that the ion optics 20 are visible from the ion guide entrance, e.g. line of sight or z-axis, through the spaces between the electrodes of the ion guide 12. A removable blocking device 22 is positioned external to the ion guide 12 but along the “line of sight” of the ion optics 20.
The ion guide 12 includes 4 curved electrodes 24A-D. The ion guide 12 has a central curved axis being co-extensive with an arc of a circular section having a radius of curvature and the x-axis extending between the ion guide entrance and the ion guide exit. A portion of the z-axis is external to the ion guide 12. In operation, the particulate matter travels along the longitudinal axis.
As shown in
In the prior art, the plane including the curved central axis is coincident with the x-axis, the ion optics are blocked by the rising section of the ion guide. This rising section of the ion guide collects the neutrals, particulants, and charged droplets. This debris increases the build up to static charges that affects the speed of ion transmission. As the debris is enclosed within the ion guide, the debris travels and collects on the ion optics.
The blocking device may be insulative or conductive. When the blocking device is conductive, the blocking device is a conductive metal post to allow grounding or being tied to a power supply.
For the embodiments shown in
The “gas stream” travels tangential to the rising section of the curved axis. The ion optics are not exposed to the gas stream.
As shown in
In the prior art, the plane including the curved central axis is coincident with the y-axis, the ion optics are blocked by the rising section of the ion guide. This rising section of the ion guide collects the neutrals, particulants, and charged droplets. This debris increases the build up to static charges that can affect the speed of ion transmission. As the debris is enclosed within the ion guide, the debris can also travel and collects on the ion optics.
In the present invention, the ion optics are not shielded by the rising section of the ion guide but shielded by the blocking device. In operation, the ions travel within the ion guide while the “gas stream” passes between the electrodes of the ion guide along the “line of sight” from the ion source to the ion optics. The debris exits the ion guide and collects on the blocking device before it can reenter the ion guide or is deflected by the blocking device.
While the ion guide has been illustratively described using curved electrodes, the concept can be extended to any ion guide, i.e. stacked ring ion guide, having an ion stream where particulate matter could reenter the ion guide and contaminate the ion optics.
Number | Name | Date | Kind |
---|---|---|---|
3859226 | Schillalies | Jan 1975 | A |
5637879 | Schueler | Jun 1997 | A |
5719403 | Purser | Feb 1998 | A |
5780863 | Benveniste et al. | Jul 1998 | A |
6396057 | Jarrell et al. | May 2002 | B1 |
6403953 | Whitehouse et al. | Jun 2002 | B2 |
6762407 | Kalinitchenko | Jul 2004 | B2 |
6891157 | Bateman et al. | May 2005 | B2 |
7952070 | Senko et al. | May 2011 | B2 |
20030155496 | Kalinitchenko | Aug 2003 | A1 |
20030222214 | Baba et al. | Dec 2003 | A1 |
20040026614 | Bateman et al. | Feb 2004 | A1 |
20080058798 | Wallace et al. | Mar 2008 | A1 |
20090159796 | Belford et al. | Jun 2009 | A1 |
20090218486 | Whitehouse et al. | Sep 2009 | A1 |
20090266984 | Hirano | Oct 2009 | A1 |
20100301227 | Muntean | Dec 2010 | A1 |
20120056110 | Distaso et al. | Mar 2012 | A1 |
Number | Date | Country |
---|---|---|
2009187771 | Aug 2009 | JP |
Entry |
---|
Michalski et al., “Ultra High Resolution Linear Ion Trap Orbitrap Mass Spectrometer (Orbitrap Elite) Facilitates Top Down LC MS/MS and Versatile Peptide Fragmentation Modes,” Molecular & Cellular Proteomics, vol. 11 (3), 2012, pp. 1-11. |
Number | Date | Country | |
---|---|---|---|
20120248304 A1 | Oct 2012 | US |