Mass spectrometry systems determine the molecular weight of chemical compounds by separating molecular ions according to their mass-to-charge ratio (m/z). Ions are generated by inducing either a loss or gain of charge and are then detected. These systems generally comprise an ionization source for producing ions (i.e. electrospray ionization (EI), atmospheric photoionization (APPI), atmospheric chemical ionization (APCI), chemical ionization (CI), fast atom bombardment, matrix assisted laser desorption ionization (MALDI) etc.), a mass filter or analyzer (i.e. quadrupole, magnetic sector, time-of-flight, ion trap etc.) for separating and analyzing ions, and an ion detector such as an electron multiplier or scintillation counter for detecting and characterizing ions.
Various ionization sources have been developed for producing ions. For instance, (ultraviolet) UV or VUV may be used to produce ions in atmospheric photoionization. This technique utilizes an ultraviolet light that applies energy to analyte molecules to split them to produce ions. Certain chemical molecules may also be employed to produce ions in chemical ionization. Lastly, various matrixes may be used in conjunction with analyte to produce ions in MALDI and AP-MALDI. Other types of ionization devices and ways of making or producing ions are well known in the art. Ionization sources continue to develop and improve. More recently, research has begun focusing on new methods, techniques and designs for producing and controlling ions. For instance, most of the ionization devices produce ions that are collected downstream. The problem with such a method is that these techniques are not completely efficient in producing ions. In addition, once the ions are produced it can be difficult to control or direct them. Often times many ions are produced and lost in the production and collection process. In addition, based on the present design of ionization devices it is difficult to effectively ionize using a combination of ionization devices. For instance, various ionization devices have been used in tandem to improve overall ion production. This technique allows for the ionization of molecules that may not be easily converted to ions using only one ionization technique. For instance, multimode ionization sources have been developed using both electropray and APPI or APCI or other similar type combinations. The problem with this technique is that it is limited to only a linear arrangement of ionization devices to produce ions. In other words, you can only ionize according to how the instrument is designed and set-up. Molecules must first be electrosprayed and then subject to APPI or APCI. This severely impacts the overall efficiency of the ion production. In addition, there are limited devices or techniques for capturing or trapping ions and then discharging or delivering them to desired places or devices.
It, therefore, would be desirable to alleviate these problems by providing a device or mass analyzer that solves all these problems. These and other problems presented have been obviated by the present invention.
The present invention relates to an apparatus and method for ion capture, storage and release. The present invention provides an ion source, comprising an ionization device for producing ions; a substrate for capturing, storing and releasing ions produced by the ionization device, a conductive material in contact with the substrate for receiving an electrical pulse; and a voltage source electrically connected to the conductive material for applying an electrical pulse to the conductive material and substrate, to release the ions captured by the substrate.
The invention also provides a mass spectrometry system. The mass spectrometry system, comprises an ion source, comprising an ionization device for producing ions; a substrate for capturing and releasing ions produced by the ionization device; a conductive material in contact with the substrate for receiving an electrical pulse; a voltage source electrically connected to the conductive material for applying an electrical pulse to the conductive material and substrate to release the ions captured by the substrate; and a detector down stream from the ion source for detecting ions.
The invention also provides a method for producing ions. The method comprises releasing the captured and stored ions from the substrate using a voltage source or similar type device.
The invention is described in detail below with reference to the following figures:
Before describing the invention in detail, it must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a substrate” includes more than one “substrate”. Reference to an “ionization device” includes more than one “ionization device”. In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below.
The term “adjacent” means contacting, spaced from, containing a portion of, near, next to or adjoining. Something adjacent may be in contact with another component, may be spaced from the other component, may contain a portion of the other component, may be near another component, may be next to or adjoining the other component. For instance, an ionization device that is adjacent to an inlet, may contact an inlet, may be spaced from an inlet, may contain a portion of an inlet, may be near an inlet, may be next to or adjoining an inlet.
The term “ion source” or “source” refers to any source that produces analyte ions.
The term “ionization device” refers to any device used for producing analyte ions.
The term “detector” refers to any device, apparatus, machine, component, or system that can detect an ion. Detectors may or may not include hardware and software. In a mass spectrometer the common detector includes and/or is coupled to a mass analyzer.
The term “substrate” refers to a material that may comprise various materials for capturing, storing and producing ions. A substrate may comprise a rigid composition with a dielectric material attached or layered on it. It also may comprise the dielectric material or a portion of it may comprise the dielectric material.
The invention is described with reference to the figures. The figures are not to scale, and in particular, certain dimensions may be exaggerated for clarity of presentation.
The mass spectrometry system 1 may be designed and configured in a number of ways. The ion source 3 may comprise an APPI ion source, an APCI ion source, a nanospray ion source, an electrospray ion source, a chemical ion source, a MALDI ion source, an AP-MALDI ion source, or a multimode ion source. Other ion sources well known in the art may also be employed for producing ions. Any number of different ion sources may be employed for producing ions. It is important to the invention that the ion source be capable of producing ions that may be captured or stored. The ion source 3 may be positioned in any number of directions, positions or locations relative to the ionization device 4. The ion source 3 can be positioned adjacent to the ionization device 4.
Referring now to
The detector 7 is generally positioned downstream from the ion source 3 and the mass analyzer 5 (See
The ionization device 4 is shown in more detail in
The substrate 8 may comprise any number of conductive and non-conductive materials. The substrate 8 may comprise a semiconductor material, a plastic type material, a resin, a thermoplastic polymer, a polymer or any other similar type materials. The material should be capable of holding or comprising a conductive material and may maintain a rigid state or structure. An electrically conductive material may comprise a portion of the substrate 8 or may be deposited on the substrate 8. In certain embodiments of the invention the conductive material may comprise one or more electrodes or electrode leads. In certain embodiments, the electrically conductive material may be positioned across the first surface 11 of the substrate 8. This is not a requirement of the invention. However, it is important to the invention that the electrically conductive material contacts the dielectric material 10. This allows an electric pulse to be carried to the dielectric material 10 from the voltage source 12.
The dielectric material comprises a first dielectric material surface 28 and a second dielectric material surface 30. The first dielectric material surface 28 contacts and captures the ions to form a sample spot 2. The second dielectric material surface 30 contacts the first substrate surface 11 or a conductive lead 27 which comprise a portion of the substrate 8. The dielectric material 10 may comprise any number of materials known in the art for capturing ions. For instance, the dielectric material 10 may comprise a polymeric material. It is important to the invention that the material be capable of capturing, storing or holding ions upon surface contact. Ideally, the material would be designed in such a way that ions in the local vicinity of the material may easily attach themselves to the material upon contact. This would not disrupt or change the charge, composition or ions themselves. Certain materials have been tested and determined to provide such properties. For instance, Captan or Mylar® materials have been particularly effective in accomplishing such tasks (For more information See Miller, S. A., et al., Science Vol. 275, 7, March 1997, entitled “Soft-Landing of Polyatomic Ions at Fluorinated Self Assembled Monolayer Surfaces”; Zoltan, T., et al., Science Vol. 306, 15 Oct. 2004, entitled “Mass Spectrometry Sampling Under Ambient Conditions with Desorption of Electrospray Ionization”; Blake, T. A., Anal. Chem. 2004, 76, 6293-6305, Preparative Linear Ion Trap Mass Spectrometer for Separation and Collection of Purified Proteins and Peptides in Arrays Using Ion Soft Landing”. All these references are herein incorporated by reference. The material must also be designed in such a way that once an electric charge or pulse is applied to the second substrate surface 13 (the opposing surface to first substrate surface 11 of substrate 8) or to the substrate 8 or its conductive material or conductive leads 27, the ions are released from the first dielectric surface 28 of the dielectric material 10 into the ionization region 6. The first dielectric surface 28 of the dielectric material 10 must be capable of capturing, storing and releasing ions under various conditions. As discussed above, the dielectric material 10 may also be designed to hold positive ions, negative ions or both. This will be dependent on the overall type of material that is employed.
Having discussed the apparatus of the invention in some detail a description of the method and operation of the invention is now in order.
It is to be understood that while the invention has been described in conjunction with the specific embodiments thereof, that the foregoing description as well as the examples that follow are intended to illustrate and not limit the scope of the invention. Other aspects, advantages and modifications within the scope of the invention will be apparent to those skilled in the art to which the invention pertains.
All patents, patent applications, and publications infra and supra mentioned herein are hereby incorporated by reference in their entireties.