Apparatus and method for performing mass spectroscopy
AssigneeWaters Technologies Corporation
InventorsScott J. Geromanos, Guo-Zhong Li, Jeffrey C. Silva, Marc V. Gorenstein, Hans Vissers
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Abstract
Embodiments of the present invention are directed to apparatus and methods for performing mass spectrometry. Data pair information is subjected to an ion audit process in which data pair information that relates to scored compounds is subtracted from the data pair information. The depleted information more readily reveals data pair information for compounds present with smaller signals.
Claims30
An apparatus for identifying compounds in a mixture by mass and chromatographic retention times comprising:
- computer processing means for being placed in signal communication with a chromatographic apparatus and a mass spectrometer, for receiving a signal from said chromatographic apparatus relating to retention time and said mass signal from said mass spectrometer, said computer processing means correlating each mass signal to a retention time signal to form a data pair and data pair information for a plurality of data pairs, storing the data pair information, and sorting said data pair information into groups defined by a range of retention times into bins, said computer processing means having data base means comprising mass and retention time information for known compounds, said computer processing means initiating an ion audit process having a first pass comprising:
- 1) specifying matching criteria for data pair information present in a bin or a plurality of bins, potentially representing a compound, to form match parameters and identifying a group of data pairs corresponding to said match parameters, said data pairs corresponding to said match parameters forming a matched set;
- 2) comparing said matched set with said data base means and identifying a compound corresponding to at least one of said match parameters and assigning an identification to said data pairs of said matched set to form a scored compound, and subtracting said data pairs of said matched set from said bins to form one or more depleted bins;
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- 3) repeating steps 1 and 2 with the data pair information held in said one or more bins and depleted bins, until said ion audit process associates all data pair information with compounds, fragments of compounds and reaction products of compounds, or said match criteria for remaining compounds, fragments of compounds and reaction products of compounds do not correspond to information in said data base, or a user defined number of repetitions.
A method of identifying a compound with chromatographic apparatus and mass spectrometry apparatus wherein chromatograph apparatus receives a sample and separates said sample into compounds by retention time, said chromatographic means producing a signal from which retention time can be determined, said mass spectrometer receives one or more compounds from said chromatographic apparatus and produces a signal corresponding to the mass of the compound, and in the event said compound forms one or more fragments, a signal corresponding to a fragment, and in the event said compound reacts to form a reaction product, a signal corresponding to said reaction product, and in the event said compound is present as a precursor, a signal corresponding to said precursor, said method comprising an ion audit process having the steps of:
- a) correlating each mass signal to a retention time signal to form a data pair and data pair information for a plurality of data pairs, storing the data pair information, and sorting said data pair information into groups defined by a range of retention times into bins;
- b) specifying matching criteria for data pair information present in a bin or a plurality of bins, potentially representing a compound, to form match parameters and identifying a group of data pairs corresponding to said match parameters, said data pairs corresponding to said match parameters forming a matched set;
- c) comparing said matched set and associated matched sets with data base means and identifying a compound corresponding to at least one of said match parameters and assigning an identification to said data pairs of said matched set to form a scored compound, and subtracting said data pairs of said matched set from said bins to form one or more depleted bins;
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- d) repeating steps b through c with the data pair information held in said one or more bins and depleted bins, until all data pair information is associated with compounds, fragments of compounds and reaction products of compounds, or said match criteria for remaining compounds, fragments of compounds and reaction products of compounds do not correspond to information in said data base, or a user defined number of repetitions.
Dependencies are inferred from the claim text.