摘要:
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.
摘要:
The present invention provides a new and improved method for quantitative determination and/or identification of proteins in a sample. In one aspect, the invention provides a mass spectroscopic method for comparing protein levels in two or more samples by differentially isotopically labeling each sample's proteins' N- or C-termini. In another aspect, the invention provides a mass-spectroscopic method for identifying a sample as source for a protein from a mixture of two or more samples by differentially isotopically labeling each sample's proteins' N- or C-termini.
摘要:
An ion sampling apparatus for use in a mass spectrometry system. The ion sampling apparatus includes a target support for receiving a sample, an irradiation source for emitting energetic radiation or particles toward the target support, and a conduit having a curved end and a longitudinal axis, the curved end having an inlet with a central axis, the conduit being adjacent to the target support. The longitudinal axis of the conduit and the central axis of the inlet intersect to define an angle that is between about 20 degrees and about 210 degrees.
摘要:
For generation and delivery of ions from an ionization chamber through an ion entrance orifice to a mass analyzer operating at high vacuum, high pass ion filtration is effected within the ionization chamber by application of electrical potentials to an electrode associated with the ion entrance orifice and to an electrode between the ionization region and the ion entrance orifice to create a retarding electric field upstream from the ion entrance orifice. The retarding electric field hinders the movement to the ion entrance orifice of ions having drift velocities below a lower limit, and as the retarding voltage gradient is made steeper, the lower limit increases.
摘要:
A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed. The apparatus and method are disclosed to analyze at least one sample which contains at least one analyte using matrix-assisted laser desorption ionization (MALDI), which apparatus comprises:The present invention relates to an apparatus and a method for ionizing at least one analyte in a sample for delivery to a mass analysis device, comprising: (a) an ionization enclosure including a passageway configured for delivery of ions to the mass analysis device; (b) means to maintain said ionization enclosure at an ambient pressure of greater than 100 mTorr; (c) a holder configured for maintaining a matrix containing said sample in the ionization enclosure at said ambient pressure; (d) a source of laser energy including means associated with the ionization enclosure for directing the laser energy onto said matrix maintained by the holder at the ambient pressure to desorb and ionize at least a portion of the analyte in the sample, and (e) means for directing at least a portion of the at least one ionized analyte into the passageway. The ambient pressure (AP-MALDI) source is compatible with various mass analyzers, particularly with mass spectrometers and solves many problems associated with conventional MALDI sources operating under vacuum. Atmospheric pressure MALDI is described. The analysis of organic molecules or fragments thereof, particularly biomolecules, e.g., biopolymers and organisms, is described.
摘要:
A mass spectrometer having a matrix-assisted laser desorption ionization (MALDI) source which operates at ambient pressure is disclosed. The apparatus and method are disclosed to analyze at least one sample which contains at least one analyte using matrix-assisted laser desorption ionization (MALDI), which apparatus comprises:The present invention relates to an apparatus and a method for ionizing at least one analyte in a sample for delivery to a mass analysis device, comprising:(a) an ionization enclosure including a passageway configured for delivery of ions to the mass analysis device;(b) means to maintain said ionization enclosure at an ambient pressure of greater than 100 mTorr;(c) a holder configured for maintaining a matrix containing said sample in the ionization enclosure at said ambient pressure;(d) a source of laser energy including means associated with the ionization enclosure for directing the laser energy onto said matrix maintained by the holder at the ambient pressure to desorb and ionize at least a portion of the analyte in the sample, and(e) means for directing at least a portion of the at least one ionized analyte into the passageway. The ambient pressure (AP-MALDI) source is compatible with various mass analyzers, particularly with mass spectrometers and solves many problems associated with conventional MALDI sources operating under vacuum. Atmospheric pressure MALDI is described. The analysis of organic molecules or fragments thereof, particularly biomolecules, e.g., biopolymers and organisms, is described.
摘要:
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.
摘要:
The present invention relates to a method for selectively delivering ions to a mass analyzer operating in a vacuum region. The method involves providing a dielectric conduit having an axial bore originating in an inlet opening that communicates with an ion source and terminating in an exit opening disposed within the vacuum region. A gas stream comprising an ion having a polarity and traveling at a drift velocity is flowed through the bore from the inlet opening toward the exit opening. A motion component is altered in a manner that does not substantially depend on the polarity of the ion to effect a change in the drift velocity of the ion. The invention also provides an apparatus to carry out the method.
摘要:
A mass spectrometer method and apparatus improve resolution and sensitivity. A voltage supply is coupled to a mass filter for applying a radio frequency voltage and for operating at at least one selected frequency. An ion optical element such as an entrance lens is driven by a voltage supply that is phase coherent with the voltage applied to the mass filter. The ion beam is tailored so that the phase space relationship of the ions is more closely matched to the acceptance of the mass filter. The ions in the incoming beam are dynamically matched to the acceptance of the mass filter over each cycle of the voltage applied to the mass filter. The ion optical element may be a single entrance lens to which is applied only a single phase coherent voltage.
摘要:
The invention provides a system apparatus and methods for fragmenting various molecules. In particular, the invention may be employed for fragmenting biomolecules like peptides to determine sequence information. The invention provides a mass spectrometry system for photo-activated collision induced dissociation. The mass spectrometry system or device includes an ion source for producing ions, a photon source adjacent to the ion source for photo-activating ions produced by the ion source, an electrical element adjacent to the photon source for creating an electric field for accelerating ions produced by the ion source and photo-activated by the photon source; wherein ions are produced by the ion source, photo-activated by the photon source and accelerated into a surface to cause dissociation of the activated ions; and a detector downstream from the ion source for detecting the collision induced and dissociated ions.Methods for molecule and/or peptide fragmentation are also disclosed.