386 results about "Desorption ionization" patented technology

A new method and system for desorption ionization is described and applied to the ionization of various compounds, including peptides and proteins present on metal, polymer, and mineral surfaces. Desorption electrospray ionization (DESI) is carried out by directing charged droplets and / or ions of a liquid onto the surface to be analyzed. The impact of the charged particles on the surface produces gaseous ions of material originally present on the surface. The resulting mass spectra are similar to normal ESI mass spectra in that they show mainly singly or multiply charged molecular ions of the analytes. The DESI phenomenon was observed both in the case of conductive and insulator surfaces and for compounds ranging from nonpolar small molecules such as lycopene, the alkaloid coniceine, and small drugs, through polar compounds such as peptides and proteins. Changes in the solution that is sprayed can be used to selectively ionize particular compounds, including those in biological matrices. In vivo analysis is demonstrated.

Improvements have been made for collection and focusing of ions generated from atmospheric pressure sources such as electrospray, atmospheric pressure chemical ionization, inductively coupled plasma, discharge, photoionization and atmospheric pressure matrix assisted laser desorption ionization. A high transmission electro-optical surface is placed between the source regions and the focusing regions to optimize the field geometries and strengths in each respective region. Compression ratios of greater than 5000 are capable of transferring virtually all ions from large volume dispersive ion regions into ion beam cross-sections of less than 1 mm. Embodiments of this invention are methods and devices for improving sensitivity of mass spectrometry when coupled to atmospheric pressure ionization sources.

Improvements have been made for collecting, focusing, and directing of ions and / or charged particles generated at atmospheric or near atmospheric pressure sources, such as but not limited to, electrospray; atmospheric pressure discharge ionization, chemical ionization, photoionization, and matrix assisted laser desorption ionization; and inductively coupled plasma ionization. A multiple-aperture laminated structure is place at the interface of two pressure regions. Electric fields geometries and strengths across the laminated structure and diameters of the apertures; all of which act to optimize the transfer of the ions from the higher pressure region into the lower pressure region while reducing the gas-load on the lower pressure region. Embodiments of this invention are methods and devices for improving sensitivity of mass spectrometry when coupled to atmospheric, near atmospheric, or higher pressure ionization sources by reducing the gas-load on the vacuum system.

A new method and system for desorption ionization is described and applied to the ionization of various compounds, including peptides and proteins present on metal, polymer, and mineral surfaces. Desorption electrospray ionization (DESI) is carried out by directing charged droplets and / or ions of a liquid onto the surface to be analyzed. The impact of the charged particles on the surface produces gaseous ions of material originally present on the surface. The resulting mass spectra are similar to normal ESI mass spectra in that they show mainly singly or multiply charged molecular ions of the analytes. The DESI phenomenon was observed both in the case of conductive and insulator surfaces and for compounds ranging from nonpolar small molecules such as lycopene, the alkaloid coniceine, and small drugs through polar compounds such as peptides and proteins. Changes in the solution that is sprayed can be used to selectively ionize particular compounds, including those in biological matrices. In vivo analysis is demonstrated.

The present invention is a device to restrict the sampling of analyte ions and neutral molecules from surfaces with mass spectrometry and thereby sample from a defined area or volume. In various embodiments of the present invention, a tube is used to sample ions formed with a defined spatial resolution from desorption ionization at or near atmospheric pressures. In an embodiment of the present invention, electrostatic fields are used to direct ions to either individual tubes or a plurality of tubes positioned in close proximity to the surface of the sample being analyzed. In an embodiment of the present invention, wide diameter sampling tubes can be used in combination with a vacuum inlet to draw ions and neutrals into the spectrometer for analysis. In an embodiment of the present invention, wide diameter sampling tubes in combination with electrostatic fields improve the efficiency of ion collection.

The invention relates to a method and device for producing ions used for analysis, in particular to an ionization method and device for producing ions through multiple modes under the lower pressure and enabling multiple ion sources to be compounded and used. According to the method and device, an electrospray ion source and other desorbing / ionization devices (such as laser desorbing ion sources) are placed in the same vacuum cavity and act on sample molecules in the vacuum cavity independently or commonly, and the irons produced by ionization are fed into an ion analyzer to be analyzed through an ion focusing device.

The invention relates to method and apparatus for production of gaseous ions from components of a condensed phase sample and analysis thereof, wherein one or more liquid jet(s) is / are directed to the surface of the sample to be investigated, where the impact of the liquid jet on the sample surface produces droplets carrying sample particles which are turned into gaseous ions via the evaporation of liquid or, if desired, by a subsequent ionization after the evaporation and the obtained sample particles are analyzed by a known method.

The present invention relates to the use of post source decay (PSD) or collision induced dissociation (CID) direct tissue (DT) MALDI-TOF or DT-MALDI-TOF-TOF mass spectrographic identification of biological molecules in a tissue or cellular sample without the need for further protein extraction. This method provides for studying cells or tissues by direct tissue MALDI (DT-MALDI), thereby substituting in situ protein release for further protein extraction. Mass / intensity data was processed with Mascot© software interrogation of the NCBI database. These results are proof of principle that DT-MALDI, combined with bioinformatics, can directly identify proteins in cells and tissues from their mass spectra.

The present invention describes devices and methods for performing protein analysis on laser capture microdissected cells, which permits proteomic analysis on cells of different populations. Particular disclosed examples are analysis of normal versus malignant cells, or a comparison of differential protein expression in cells that are progressing from normal to malignant. The protein content of the microdissected cells may be analyzed using techniques such as immunoassays, 1D and 2D gel electrophoresis characterization, Western blotting, liquid chromatography quadrapole ion trap electrospray (LCQ-MS), Matrix Assisted Laser Desorption Ionization / Time of Flight (MALDI / TOF), and Surface Enhanced Laser Desorption Ionization Spectroscopy (SELDI). In addition to permitting direct comparison of qualitative and quantitative protein content of tumor cells and normal cells from the same tissue sample, the methods also allow for investigation of protein characteristics of tumor cells, such as binding ability and amino acid sequence, and differential expression of proteins in particular cell populations in response to drug treatment. The present methods also provide, through the use of protein fingerprinting, a rapid and reliable way to identify the source tissue of a tumor metastasis.

The invention relates to a method and a device thereof, which adopt a mode of rising the temperature gradually under normal pressure to carry out desorption ionization in sequence on mixed objects to be tested on the solid surface and carry out continuous and multiple data acquisition in the process of desorption ionization gradually. The invention leads the objects to be tested with different thermal desorption capabilities to be desorbed out of the surface of the solid object to be tested by rising the temperature of at least one part of samples gradually, thus providing a means for pre-separating mixed samples so as to reduce the difficulty for subsequent mass spectrometric detection. Simultaneously, the invention acquires mass spectrometric data for multiple times for objects to be tested with various boiling points in the process of rising temperature so as to lead the objects to be tested with low boiling point not to be consumed completely quickly due to high temperature, thus improving the detection efficiency of the objects to be tested with lower boiling points.

A new ionization source named Surface Activated Chemical Ionization (SACI) has been discovered and used to improve the sensitivity of the mass spectrometer. According to this invention the ionization chamber of a mass spectrometer is heated and contains a physical new surface to improve the ionization process. The analyte neutral molecules that are present in gas phase are ionized on this surface. The surface can be made of various materials and may also chemically modified so to bind different molecules. This new ionization source is able to generate ions with high molecular weight and low charge, an essential new key feature of the invention so to improve sensitivity and reduce noise. The new device can be especially used for the analysis of proteins, peptides and other macromolecules. The new invention overcomes some of the well known and critical limitations of the Electrospray (ESI) and Matrix Assisted Laser Desorption Ionization (MALDI) mass spectrometric techniques.

An electrospray-assisted laser desorption ionization device includes: an electrospray unit including a nozzle; a voltage supplying member disposed to establish between the nozzle and a receiving unit a potential difference such that liquid drops of the electrospray medium formed at the nozzle are laden with charges, and such that the liquid drops are forced to leave the nozzle toward the receiving unit along a traveling path; a laser desorption unit adapted to irradiate a sample such that, upon irradiation, analytes contained in the sample are desorbed to fly along a flying path which intersects the traveling path so as to enable the analytes to be occluded in the liquid drops, and such that as a result of dwindling in size of the liquid drops when moving along the traveling path, charges of the liquid drops will pass on to the analytes occluded therein to form ionized analytes.

The invention relates to a desorption ionization device which carries out desorption to a measured object with a solid surface at atmospheric pressure by laser and then carries out ionization to the object after desorption by utilizing vacuum-ultraviolet light. The device comprises a laser generating laser beams, an optical laser system used for converging the laser beams on the surface of the measured object so as to lead the measured object in the sample to be desorbed or gasified, and an ultraviolet lamp which is arranged near the desorbed or gasified part and gives off ultraviolet rays soas to lead molecules of at least one part of the desorbed or gasified object to be ionized. Being combined with a spraying apparatus, the desorption ionization device has higher ionization efficiencyto nonpolar or low-polar micromolecules. The desorption ionization device can be applicable to fast sync analysis of complex mixtures with different polarities and molecular weights by utilizing vacuum-ultraviolet light / electron spray. Meanwhile, the design of the multichannel chamber structural keeps the local concentration of each component in an ion source effectively when a test is carried out, thereby improving the ionization efficiency.

Atmospheric pressure, intermediate pressure and vacuum laser desorption ionization methods and ion sources are configured to increase ionization efficiency and the efficiency of transmitting ions to a mass to charge analyzer or ion mobility analyzer. An electric field is applied in the region of a sample target to accumulate ions generated from a local ion source on a solid or liquid phase sample prior to applying a laser desorption pulse. The electric field is changed just prior to or during the desorption laser pulse to promote the desorption of charged species and improve the ionization efficiency of desorbed sample species. After a delay, the electric field may be further changed to optimize focusing and transmission of ions into a mass spectrometer or ion mobility analyzer. Charged species may also be added to the region of the laser desorbed sample plume to promote ion-molecule reactions between the added ions and desorbed neutral sample species, increasing desorbed sample ionization efficiency and / or creating desired product ion species. The cycling of electric field changes is repeated in a timed sequence with one or more desorption laser pulse occurring per electric field change cycle. Embodiments of the invention comprise atmospheric pressure, intermediate pressure and vacuum pressure laser desorption ionization source methods and devices for increasing the analytical flexibility and improving the sensitivity of mass spectrometric analysis.