The invention describes a new method to sequence DNA. The improvements over the existing DNA sequencing technologies are high speed, high throughput, no electrophoresis and gel reading artifacts due to the complete absence of an electrophoretic step, and no costly reagents involving various substitutions with stable isotopes. The invention utilizes the Sanger sequencing strategy and assembles the sequence information by analysis of the nested fragments obtained by base-specific chain termination via their different molecular masses using mass spectrometry, as for example, MALDI or ES mass spectrometry. A further increase in throughput can be obtained by introducing mass-modifications in the oligonucleotide primer, chain-terminating nucleoside triphosphates and/or in the chain-elongating nucleoside triphosphates, as well as using integrated tag sequences which allow multiplexing by hybridization of tag specific probes with mass differentiated molecular weights.

Dna sequencing by mass spectrometry

The invention provides fast and highly accurate mass spectrometer based processes for detecting a particular nucleic acid sequence in a biological sample. Depending on the sequence to be detected, the processes can be used, for example, to diagnose a genetic disease or chromosomal abnormality; a predisposition to a disease or condition, infection by a pathogenic organism, or for determining identity or heredity.

DNA diagnostics based on mass spectrometry

Matrix assisted laser desorption/ionization is performed in a manner to thermalize large analyte ions in a plume of desorbed material for spectroscopic analysis. The thermalized ions have a low or zero mean velocity and are presented at a well-defined instant in time, reducing artifacts and sharpening the spectral peaks. In one embodiment the light is delivered to a matrix or sample holder having a cover, baffle or compartment. The baffle or compartment impedes or contains a plume of desorbed material and the analyte undergoes collisions to lower its mean velocity and directionality. Thus "thermalized", the analyte ions are passed to a mass analysis instrument. In a preferred embodiment, an optical fiber butts up against a thin transparent plate on which the specimen resides, with the matrix side in a vacuum acceleration chamber. A mechanical stage moves the specimen in both the x- and y-directions to select a point on the specimen which is to receive the radiation. The use of a fiber optic illuminator allows the entire stage assembly to be subsumed essentially within the dimensions of a conventional stage.

Method and apparatus for maldi analysis

Mixtures containing a biological macromolecule, such as a nucleic acid molecule or a polypeptide, and a liquid matrix, which absorbs infrared (IR) radiation, are provided. These mixtures are useful for analysis of the biological macromolecule by IR matrix assisted laser desorption/ionization (IR-MALDI) mass spectrometry. Also provided are processes for analyzing a biological macromolecule using IR-MALDI mass spectrometry. For example, processes for detecting the presence or identity of a biological macromolecule in a sample, or for sequencing a biological macromolecule are provided.

Infrared matrix-assisted laser desorption/ionization mass spectrometric analysis of macromolecules

Processes and kits for immobilizing a high density of nucleic acids on an insoluble surface, which are particularly useful for mass spectrometric detection of nucleic acids, are disclosed. Arrays containing the immobilized nucleic acids and use of the immobilized nucleic acids in a variety of solid phase nucleic acid chemistry applications, including nucleic acid synthesis (chemical and enzymatic), hybridization and/or extension, and sequencing, are provided. Serial and parallel dispensing tools that can deliver defined volumes of fluid to generate multi-element arrays of sample material on a substrate surface are further provided. Tools provided herein can include an assembly of vesicle elements, or pins, wherein each of the pins can include a narrow interior chamber suitable for holding nanoliter volumes of fluid. Methods for dispensing tools that can be employed to generate multi-element arrays of sample material on a substrate surface are also provided. The tool can dispense a spot of fluid to a substrate surface by spraying the fluid from the pin, contacting the substrate surface or forming a drop that touches against the substrate surface. The tool can form an array of sample material by dispensing sample material in a series of steps, while moving the pin to different locations above the substrate surface to form the sample array. The prepared sample arrays may be passed to a plate assembly that disposes the sample arrays for analysis by mass spectrometry.

High density immobilization of nucleic acids

Sputter initiated resonance ionization spectrometry.

A health physics instrument simulator system permitting an operator to simulate measurement of radiation levels of a plurality of radiation types includes a memory for storing first data corresponding to an n-dimensional training space representing a predetermined physical location, second data defining a radiation source including source strength, source type and source location with respect to the training space and radiation intensity data based on the second data, where each of the radiation intensity data corresponds to one respective location in the training space, a selecting device for selecting a predetermined simulated radiation sensing instrument, a pointing device for identifying a location within the training space defining a current location of the simulated radiation sensing instrument and a display for displaying both an instrument display corresponding to the simulated radiation sensing instrument and radiation intensity data corresponding to the current location in the training space. Methods for operating a health physics instrument simulator system including a computer and a display are also disclosed.

Instrument simulator system

Apparatus and methods of operation are described for determining, with isotopic selectivity, the number of noble gas atoms in a sample. The analysis is conducted within an evacuated chamber which can be isolated by a valve from a vacuum pumping system capable of producing a pressure of 10 -8 Torr. Provision is made to pass pulses of laser beams through the chamber, these pulses having wavelengths appropriate for the resonance ionization of atoms of the noble gas under analysis. A mass filter within the chamber selects ions of a specific isotope of the noble gas, and means are provided to accelerate these selected ions sufficiently for implantation into a target. Specific types of targets are discussed. An electron measuring device produces a signal relatable to the number of ions implanted into the target and thus to the number of atoms of the selected isotope of the noble gas removed from the gas sample. The measurement can be continued until a substantial fraction, or all, of the atoms in the sample have been counted. Furthermore, additional embodiments of the apparatus are described for bunching the atoms of a noble gas for more rapid analysis, and for changing the target for repetitive cycling of the gas in the chamber. The number of repetitions of the cyclic steps depend upon the concentration of the isotope of interest, the separative efficiency of the mass filter, etc. The cycles are continued until a desired selectivity is achieved. Also described are components and a method of operation for a pre-enrichment operation for use when an introduction of a total sample would elevate the pressure within the chamber to levels in excess of those for operation of the mass filter, specifically a quadrupole mass filter. Specific examples of three noble gas isotope analyses are described.

Method and apparatus for noble gas atom detection with isotopic selectivity

A fundamentally new technique for the measurement of the number of subexcitation electrons produced by the passage of ionizing radiation (electromagnetic and high energy charged particles) through a gas has been developed by us during the past few years [1–5] The new detector is based on the digital characterization of the electrons in the particle track produced by the ionizing radiation where the charged particle track is registered by measuring the number of electrons found in given subvolumes of the gas in the ionization chamber [6–10] The track is thus characterized by a set of integers in each volume element, from which parameters such as the track length and energy can be measured We have specifically developed this technique for use in the field of microdosimetry, where the study of the fluctuations in the energy deposition in the charged particle track on the order of the molecular to cellular (i e, nanometers to microns) dimensions is important in understanding the chemical and biological effects of ionizing radiation [2,4,6] If the charged particle is a recoil nucleus produced by a neutron interaction, the energy deposited and the linear energy transfer can be inferred from this information, allowing the detector to act as neutron spectrometer [3, 11] In principle, the detector can be used for any application that requires knowledge of the three dimensional locations of single electrons in a gas [1,12]

/pdf/electrical-breakdown-and-optical-emission-properties-of-high-2h764ry5z6.pdf

G. Samuel Hurst

Papers

Sputter initiated resonance ionization spectrometry.

Instrument simulator system

Method and apparatus for noble gas atom detection with isotopic selectivity

Electrical Breakdown and Optical Emission Properties of High Pressure Pulsed RF Gas Discharges