Systems and methods for processing fragment ion spectra to determine mechanism of fragmentation and structure of molecule

1. A system for grouping fragment ions of a molecule and determining a fragmentation pathway for the molecule using mass spectrometry with ramps in collision energy, comprising:

a mass spectrometer that fragments and analyzes a known molecule using a plurality of different collision energies producing a plurality of variables for a plurality of fragment ions, wherein the plurality of variables include intensities for mass-to-charge ratio (m/z) values of the plurality of fragment ions for the plurality of different collision energies; and

a processor that

performs principal component analysis on the plurality of variables,

selects a number of principal components produced by the principal component analysis,

creates a subset principal component space having the number of principal components,

(a) selects a variable in the subset principal component space,

(b) defines a spatial angle around a vector extending from an origin to the variable,

(c) selects a set of one or more variables within the spatial angle of the vector,

(d) assigns the set to a group, if the set comprises a minimum number of variables, wherein the group identifies correlated variables and wherein the minimum number of variables is a number of correlated variables a group is expected to include, and

(e) removes the set of one or more variables from further analysis and repeats steps (a)-(e) until remaining variables not assigned to a group do not exceed a threshold, producing a plurality of groups,

orders the plurality of groups by collision energy,

selects the variables for at least one fragment ion from each of two or more of the ordered plurality of groups, and

compares the selected fragment ions or the variables of the selected fragment ions to determine a fragmentation pathway for the known molecule.

2. The system of claim 1 , wherein the processor compares the variables of the selected fragment ions to determine a fragmentation pathway for the known molecule by creating a profile plot that includes the variables of the selected fragment ions plotted as a function of collision energy.

3. The system of claim 2 , wherein the processor compares peak shapes of the variables of the selected fragment ions plotted as a function of collision energy in the profile plot to determine the fragmentation pathway.

4. The system of claim 2 , wherein the processor compares peak intensities of the variables of the selected fragment ions plotted as a function of collision energy in the profile plot to determine the fragmentation pathway.

5. The system of claim 1 , wherein the processor compares the selected fragment ions to determine a fragmentation pathway for the known molecule by comparing the m/z values of the selected fragment ions.

6. A method for grouping fragment ions of a molecule and determining a fragmentation pathway for the molecule using mass spectrometry with ramps in collision energy, comprising:

obtaining a plurality of variables for a plurality of fragment ions produced by a mass spectrometer that fragments and analyzes a known molecule using a plurality of different collision energies, wherein the plurality of variables include intensities for mass-to-charge ratio (m/z) values of the plurality of fragment ions for the plurality of different collision energies;

performing principal component analysis on the plurality of variables;

selecting a number of principal components produced by the principal component analysis;

creating a subset principal component space having the number of principal components;

(a) selecting a variable in the subset principal component space;

(b) defining a spatial angle around a vector extending from an origin to the variable;

(c) selecting a set of one or more variables within the spatial angle of the vector;

(d) assigning the set to a group, if the set comprises a minimum number of variables, wherein the group identifies correlated variables and wherein the minimum number of variables is a number of correlated variables a group is expected to include; and

(e) removing the set of one or more variables from further analysis and repeating steps (a)-(e) until remaining variables not assigned to a group do not exceed a threshold, producing a plurality of groups;

ordering the plurality of groups by collision energy;

selecting the variables for at least one fragment ion from each of two or more of the ordered plurality of groups; and

comparing the selected fragment ions or the variables of the selected fragment ions to determine a fragmentation pathway for the known molecule.

7. The method of claim 6 , wherein comparing the selected fragment ions or the variables of the selected fragment ions to determine a fragmentation pathway for the known molecule comprises creating a profile plot that includes the variables of the selected fragment ions plotted as a function of collision energy.

8. The method of claim 7 , further comprising comparing peak shapes of the variables of the selected fragment ions plotted as a function of collision energy in the profile plot to determine the fragmentation pathway.

9. The method of claim 7 , further comprising comparing peak intensities of the variables of the selected fragment ions plotted as a function of collision energy in the profile plot to determine the fragmentation pathway.

10. The method of claim 6 , wherein comparing the selected fragment ions to determine a fragmentation pathway for the known molecule comprises comparing the m/z values of the selected fragment ions.

11. 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 grouping fragment ions of a molecule and determining a fragmentation pathway for the molecule using mass spectrometry with ramps in collision energy, the method comprising:

providing a system, wherein the system comprises one or more distinct software modules, and wherein the distinct software modules comprise a measurement module and a grouping module;

obtaining a plurality of variables for a plurality of fragment ions produced by a mass spectrometer that fragments and analyzes a known molecule using a plurality of different collision energies using the measurement module, wherein the plurality of variables include intensities for mass-to-charge ratio (m/z) values of the plurality of fragment ions for the plurality of different collision energies;

performing principal component analysis on the plurality of variables using the grouping module;

selecting a number of principal components produced by the principal component analysis using the grouping module;

creating a subset principal component space having the number of principal components using the grouping module;

(a) selecting a variable in the subset principal component space using the grouping module;

(b) defining a spatial angle around a vector extending from an origin to the variable using the grouping module;

(c) selecting a set of one or more variables within the spatial angle of the vector using the grouping module;

(d) assigning the set to a group, if the set comprises a minimum number of variables using the grouping module, wherein the group identifies correlated variables and wherein the minimum number of variables is a number of correlated variables a group is expected to include; and

(e) removing the set of one or more variables from further analysis and repeating steps (a)-(e) until remaining variables not assigned to a group do not exceed a threshold using the grouping module, producing a plurality of groups;

ordering the plurality of groups by collision energy using the grouping module;

selecting the variables for at least one fragment ion from each of two or more of the ordered plurality of groups using the grouping module; and

comparing the selected fragment ions or the variables of the selected fragment ions to determine a fragmentation pathway for the known molecule using the grouping module.

12. The computer program product of claim 11 , wherein comparing the selected fragment ions or the variables of the selected fragment ions to determine a fragmentation pathway for the known molecule comprises creating a profile plot that includes the variables of the selected fragment ions plotted as a function of collision energy.

13. The computer program product of claim 12 , further comprising comparing peak shapes of the variables of the selected fragment ions plotted as a function of collision energy in the profile plot to determine the fragmentation pathway.

14. The computer program product of claim 12 , further comprising comparing peak intensities of the variables of the selected fragment ions plotted as a function of collision energy in the profile plot to determine the fragmentation pathway.

15. The computer program product of claim 11 , wherein comparing the selected fragment ions to determine a fragmentation pathway for the known molecule comprises comparing the m/z values of the selected fragment ions.