Patent ID: 8575543

Claim:
A method for analyzing a structure of a substance of interest, comprising: (a) performing a measurement of triple quadrupole mass spectrometry with respect to the substance of interest while varying a value of CID energy; (b) at given values of CID energy, calculating percentages of precursor ion contents to a total ion content, and percentages of product ion contents, each having specific m/z values, to the total ion content; (c) extracting values of the percentages of product ion contents, each having specific m/z values, to the total ion content, wherein said values are values of the percentages of product ion contents at the respective values of CID energy which give respective values of the percentages of the precursor ion contents to the total ion content calculated in step (b); (d) calculating sums of all combinations of the values of the percentages of product ion contents, each having specific m/z values, to the total ion content extracted in step (c); and (e) from functions where the values of percentages of precursor ion contents to the total ion content are assigned as x and where the calculated values of the sums of combinations are assigned as y, selecting those which can be straight-line approximated, and analyzing the structure of the substance of interest, based on m/z values of product ions which each give the selected functions.