Abstract: A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed.

Abstract: A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed.

Abstract: A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed.

Abstract: A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed.

Abstract: A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed.

Abstract: A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed.

Abstract: A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed.

Abstract: An atmospheric pressure ion source, e.g. for a mass spectrometer, that produces ions by atmospheric pressure photoionization (APPI). It includes a vaporizer, a photon source for photoionizing vapor molecules upon exit from the vaporizer, a passageway for transporting ions to, for example, a mass spectrometer system, and a means for directing the ions into the passageway. The center axis of the vaporizer and the center axis of the passageway form an angle that may be about 90 degrees. Included in the invention is a method for creating ions by atmospheric pressure photoionization along an axis and directing them into a passageway oriented at an angle to that axis.

Abstract: An apparatus and method for calibrating a mass spectrometer by internally introducing calibration masses at a post-source stage of the mass spectrometer is provided. A source of lock mass ions adjacent the ion optics creates lock mass ions within the ion optics. Lock mass ions mix with the analyte ions in the ion optics prior to mass analysis. The source of lock mass ions may include various means for ionizing lock mass molecules including but not limited to photoionization, field desorption-ionization, electron ionization, and thermal ionization means. An apparatus and method of mass calibrating a tandem mass spectrometer is also provided. The mass calibration apparatus includes a collision cell for fragmenting analyte ions and a source of lock mass ions adjacent said collision cell for creating lock mass ions in the collision cell.

Abstract: A method of identifying a biopolymer in a sample that includes one or more biopolymers. The biopolymers may be polypeptides, polynucleotides, or polysaccharides. The method makes use of mass spectral datasets. A first dataset includes measured masses of the one or more biopolymers that are in the sample. A second dataset includes measured masses of a collection of fragments of the one or more biopolymers. The method selects a mass from the first dataset and then matches masses from the second dataset with the selected mass. The matched masses represent fragments of the biopolymer with the selected mass. Once the masses in the second dataset have been matched they are compared to determine a monomer sequence for the biopolymer with the selected mass. The method may be repeated with additional masses in the first dataset.

Abstract: A fraction collection system for liquid chromatography includes a conduit, which directs a sample eluent from an LC column through a flow splitter to a destructive analytical detector such as a mass spectrometer to analyze sample components, and to a fraction collector. A nondestructive detector such as a photodetector is positioned near the fraction collector to detect arrival of sample components. Optionally, a nondestructive detector such as a photodetector is situated upstream from the splitter, to detect passing sample components. Time intervals between detection of a calibrant or a sample component at any two of the detectors provide for automatable identification of selected sample components at the sample collector.

Abstract: The present invention provides a new and improved method for reducing the complexity of a proteomic sample, and preferably also for allowing identification of proteins in the sample. In one aspect, the invention provides a highly efficient method for identifying proteins in a proteomic sample by characterizing a single N-terminal peptide per protein. In another aspect, the invention provides a method for identifying proteins in a proteomic sample by characterizing a single C-terminal peptide per protein.

Abstract: The present invention provides an apparatus and method for use with a mass spectrometer. The multimode ionization source of the present invention provides one or more atmospheric pressure ionization sources (e.g., electrospray, atmospheric pressure chemical ionization and/or atmospheric pressure photoionization) for ionizing molecules. A method of producing ions using the multimode ionization source is also disclosed. The apparatus and method provide the advantages of the combined ion sources without the inherent disadvantages of the individual sources. In an embodiment, the multimode ionization source includes an infrared emitter enclosed in an inner chamber for drying a charged aerosol. ESI/APCI multimode sources may include a corona needle shield and/or an auxiliary electrode.

Abstract: An apparatus and method for calibrating a mass spectrometer by internally introducing calibration masses at a post-source stage of the mass spectrometer is provided. A source of lock mass ions adjacent the ion optics creates lock mass ions within the ion optics. Lock mass ions mix with the analyte ions in the ion optics prior to mass analysis. The source of lock mass ions may include various means for ionizing lock mass molecules including but not limited to photoionization, field desorption-ionization, electron ionization, and thermal ionization means. An apparatus and method of mass calibrating a tandem mass spectrometer is also provided. The mass calibration apparatus includes a collision cell for fragmenting analyte ions and a source of lock mass ions adjacent said collision cell for creating lock mass ions in the collision cell.

Abstract: The present invention provides novel systems for sequencing nucleic acid molecules using dNTPs that are 3′ end labeled with cleavable tags that block further extension and uniquely identify the bases to which they are attached. Removal of the tags liberates the 3′ ends of the extension products for further extension. In related embodiments, oligonucleotides containing sequence-related cleavable tags are employed in a ligation reaction to determine the sequence of a particular DNA sample.

Abstract: For delivery of ions from a higher pressure ion source to a mass analyzer operating at high vacuum, high pass ion filtration is effected within a dielectric capillary interface between the higher pressure ionization chamber and the lower pressure environment of a mass analyzer, by application of electrical potentials to end electrodes and to at least one electrode associated with the dielectric capillary between the ends, to create an end-to-end electric field generally opposing gas flow-assisted movement of ions from the upstream end to the downstream end, and to create a steeper voltage gradient along an upstream portion than along a downstream portion of the capillary. The voltage gradient along the steeper upstream portion of the capillary is sufficiently steep to cause ions having drift velocities below a lower limit to stall within the capillary. The respective potentials may be adjusted to increase the steepness of the upstream voltage gradient to increase the drift velocity lower limit.

Abstract: An atmospheric pressure ion source, e.g. for a mass spectrometer, that produces ions by atmospheric pressure photoionization (APPI). It includes a vaporizer, a photon source for photoionizing vapor molecules upon exit from the vaporizer, a passageway for transporting ions to, for example, a mass spectrometer system, and a means for directing the ions into the passageway. The center axis of the vaporizer and the center axis of the passageway form an angle that may be about 90 degrees. Included in the invention is a method for creating ions by atmospheric pressure photoionization along an axis and directing them into a passageway oriented at an angle to that axis.

Abstract: An apparatus and method for calibrating a mass spectrometer by internally introducing calibration masses at a post-source stage of the mass spectrometer is provided. A source of lock mass ions adjacent the ion optics creates lock mass ions within the ion optics. Lock mass ions mix with the analyte ions in the ion optics prior to mass analysis. The source of lock mass ions may include various means for ionizing lock mass molecules including but not limited to photoionization, field desorption-ionization, electron ionization, and thermal ionization means. An apparatus and method of mass calibrating a tandem mass spectrometer is also provided. The mass calibration apparatus includes a collision cell for fragmenting analyte ions and a source of lock mass ions adjacent said collision cell for creating lock mass ions in the collision cell.

Abstract: Apparatus and methods are disclosed for an ion source that comprises a flow-through ultraviolet lamp for photoionization. One embodiment of the apparatus comprises a tubular outer element and a tubular inner element. The inner element is disposed within the outer element to provide a space between the inner and outer elements. The inner element is open at its ends to provide a pathway through that element. A gas discharge between the elements produces ultraviolet radiation, which transmits through the wall of the inner element into the region within the inner element and ionizes molecules that flow through the region. The ion source can be employed in conjunction with a mass analyzer for mass spectrometry. In the method for ionizing molecules in an ion source, vaporized molecules are flowed through the region within the inner element, the region being surrounded by UV radiation. The radiation ionizes vaporized molecules in the surrounded region.

Abstract: The present invention provides an apparatus and method for use with a mass spectrometer. The multimode ionization source of the present invention provides one or more atmospheric pressure ionization sources (i.e. electrospray, atmospheric pressure chemical ionization and/or atmospheric pressure photoionization) for ionizing molecules. A method of producing ions using the multimode ionization source is also disclosed. The apparatus and method provide the advantages of the combined ion sources without the inherent disadvantages of the individual sources.