Method and apparatus for desorption and ionization of analytes
First Claim
1. An apparatus for measuring the mass of analyte molecules by means of mass spectrometry, said apparatus comprising:
- a spectrometer tube;
vacuum means for applying a vacuum to the interior of said tube;
electrical potential means within the tube for applying an accelerating electrical potential to desorbed analyte molecules;
sample presenting means removably insertable into said spectrometer means, for presenting said analyte molecules in association with a matrix material for promoting desorption and ionization of said analyte molecules, said sample presenting means being adapted to present said analyte molecules on or above the surface of said matrix material, whereby at least a portion of said analyte molecules not consumed in said mass spectrometry analysis will remain accessible for subsequent chemical analytical procedures;
laser beam means for producing a laser beam directed to said analyte molecules and matrix material on said sample presenting means inserted into said spectrometer means, for imparting sufficient energy to desorb and ionize a portion of said analyte molecules on said sample presenting means; and
detector means associated with said spectrometer tube for detecting the impact of accelerated ionized analyte molecules thereon.
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Abstract
This invention relates generally to methods and apparatus for desorption and ionization of analytes for the purpose of subsequent scientific analysis by such methods, for example, as mass spectrometry or biosensors. More specifically, this invention relates to the field of mass spectrometry, especially to the type of matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry used to analyze macromolecules, such as proteins or biomolecules. Most specifically, this invention relates to the sample probe geometry, sample probe composition, and sample probe surface chemistries that enable the selective capture and desorption of analytes, including intact macromolecules, directly from the probe surface into the gas (vapor) phase without added chemical matrix.
39 Citations
31 Claims
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1. An apparatus for measuring the mass of analyte molecules by means of mass spectrometry, said apparatus comprising:
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a spectrometer tube;
vacuum means for applying a vacuum to the interior of said tube;
electrical potential means within the tube for applying an accelerating electrical potential to desorbed analyte molecules;
sample presenting means removably insertable into said spectrometer means, for presenting said analyte molecules in association with a matrix material for promoting desorption and ionization of said analyte molecules, said sample presenting means being adapted to present said analyte molecules on or above the surface of said matrix material, whereby at least a portion of said analyte molecules not consumed in said mass spectrometry analysis will remain accessible for subsequent chemical analytical procedures;
laser beam means for producing a laser beam directed to said analyte molecules and matrix material on said sample presenting means inserted into said spectrometer means, for imparting sufficient energy to desorb and ionize a portion of said analyte molecules on said sample presenting means; and
detector means associated with said spectrometer tube for detecting the impact of accelerated ionized analyte molecules thereon.
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2. A method in mass spectrometry to measure the mass of an analyte molecule, said method comprising the steps of:
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derivitizing a surface on a probe tip face with an affinity reagent having means for selectively bonding with an analyte molecule;
exposing said derivitized probe tip face to a source of said analyte molecule so as to bond said analyte molecule thereto;
placing the probe tip into one end of a time-of-flight mass spectrometer and applying a vacuum and an electric field to form an accelerating potential within the spectrometer;
striking the probe tip face within the spectrometer with a series of laser pulses in order to desorb ions of said analyte molecules from said tip;
detecting the mass weights of the ions by their time of flight within said mass spectrometer; and
displaying such detected mass weights. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of measuring the mass of analyte molecules by means of laser desorption/ionization, time-of-flight mass spectrometry in which a matrix material is used in conjunction with said analyte molecules for facilitating desorption and ionization of the analyte molecules, the improvement comprising:
presenting the analyte molecules on or above the surface of the matrix material, whereby at least a portion of the analyte molecules not desorbed in said mass spectrometry analysis remain chemically accessible for subsequent analytical procedures, in situ, on said probe tip, without the necessity for separating said portion of said analyte molecules from said matrix material.
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14. An apparatus for facilitating desorption and ionization of analyte molecules for analysis by mass spectrometry, said apparatus comprising:
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a substrate; and
an affinity reagent attached to said substrate and having means for selectively bonding with said analyte molecules. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for preparing a surface for presenting analyte molecules for analysis by time-of-flight mass spectrometry, said method comprising:
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providing a substrate on said surface for supporting said analyte;
derivitizing said substrate with an affinity reagent having means for selectively bonding with said analyte; and
depositing a desorption/ionization promoting matrix material on said substrate in association with said affinity reagent, said matrix material being deposited in a manner so as to not render ineffective said means on said affinity reagent for selectively bonding with said analyte.
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26. A method for preparing a surface for presenting analyte molecules for analysis, said method comprising;
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providing a substrate on said surface for supporting said analyte;
derivitzing said substrate with an affinity reagent having means for selectively bonding with said analyte; and
a means for detection of said analyte molecules bonded with said affinity reagent. - View Dependent Claims (27, 28, 29, 30, 31)
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Specification