US 11,456,164 B2 · Systems and methods for identifying compounds from MS/MS data without precursor ion information

Abstract

Systems and methods are provided for identifying a precursor ion without using any a priori precursor ion information. In one method, a sample is analyzed using a tandem mass spectrometer, producing at least one measured product ion spectrum from a precursor mass-to-charge ratio range. The at least one measured product ion spectrum are received. A subset of measured product ions is selected from the at least one measured product ion spectrum. A list of candidate compounds is created by searching a dictionary of potential compounds that includes one or more predicted product ions for each of the potential compounds using the subset of measured product ions. A candidate compound on the list is selected as the identified compound. In another method, the measured product ions are assumed to correspond to shortened forms of the peptide and a protein database is searched for shortened forms of the peptide.

Claims20

Dependent claims

A system for identifying a compound from tandem mass spectrometry product ions without using any a priori precursor ion information, comprising:

a tandem mass spectrometer that analyzes a sample producing at least one measured product ion spectrum from a precursor mass-to-charge ratio range;
and
a processor in communication with the tandem mass spectrometer that
(a) receives the at least one measured product ion spectrum from the tandem mass spectrometer,
(b) selects a measured product ion from the at least one measured product ion spectrum,
(c) creates a list of candidate compounds by searching a dictionary of potential compounds with a mass of the selected measured product ion, wherein the dictionary includes one or more predicted product ions for each of the potential compounds and wherein the dictionary is searched using a key that is a product ion mass to retrieve the list of candidate compounds that could produce the product ion mass, and
(d) for each compound of the list of candidate compounds, comparing one or more predicted product ions found from the dictionary to the at least one measured product ion spectrum to identify at least one compound of the list of candidate compounds with a highest number of predicted product ions matching the at least one measured product ion spectrum.

4 more elements

A method for identifying a compound from tandem mass spectrometry product ions without using any a priori precursor ion information, comprising:

(a) analyzing a sample using a tandem mass spectrometer, producing at least one measured product ion spectrum from a precursor mass-to-charge ratio range;
(b) receiving the at least one measured product ion spectrum from the tandem mass spectrometer using a processor;
(c) selecting a measured product ion from the at least one measured product ion spectrum using the processor;
(d) creating a list of candidate compounds by searching a dictionary of potential compounds with a mass of the selected measured product ion, wherein the dictionary includes one or more predicted product ions for each of the potential compounds and wherein the dictionary is searched using a key that is a product ion mass to retrieve the list of candidate compounds that could produce the product ion mass using the processor;
and
(e) for each compound of the list of candidate compounds, comparing one or more predicted product ions found from the dictionary to the at least one measured product ion spectrum to identify at least one compound of the list of candidate compounds with a highest number of predicted product ions matching the at least one measured product ion spectrum.

3 more elements

A computer program product, comprising a non-transitory and tangible computer-readable storage medium whose contents include a program with instructions being executed on a processor so as to perform a method for identifying a precursor ion from tandem mass spectrometry product ions without using any a priori precursor ion information, the method comprising:

(a) providing a system, wherein the system comprises one or more distinct software modules, and wherein the distinct software modules comprise a measurement module and an identification module;
(b) receiving from a tandem mass spectrometer at least one measured product ion spectrum from a precursor mass-to-charge ratio range produced by analyzing a sample using the measurement module;
(c) selecting a measured product ion from the at least one measured product ion spectrum using the identification module;
(d) creating a list of candidate compounds by searching a dictionary of potential compounds with a mass of the selected measured product ion, wherein the dictionary includes one or more predicted product ions for each of the potential compounds and wherein the dictionary is searched using a key that is a product ion mass to retrieve the list of candidate compounds that could produce the product ion mass using the identification module;
and
(e) for each compound of the list of candidate compounds, comparing one or more predicted product ions found from the dictionary to the at least one measured product ion spectrum to identify at least one compound of the list of candidate compounds with a highest number of predicted product ions matching the at least one measured product ion spectrum using the identification module.

3 more elements

Dependencies are inferred from the claim text.

Systems and methods for identifying compounds from MS/MS data without precursor ion information

Life of this patent

Systems and methods for identifying compounds from MS/MS data without precursor ion information

Life of this patent

Abstract

Claims20