Patent ID: 8180576

Claim:
A mass spectrometer that performs an MS n analysis in which a process of selecting an ion having a specific mass-to-charge ratio from among ions produced by an MS n-1 (where n is an integer equal to or more than 2) analysis, dissociating the ion, and performing a mass analysis of ions generated by a dissociation is repeated for n−1 stages, the MS n analysis including a plurality of MS m analyses while making m increase from 1 up to n, comprising: a detector that detects data obtained by each MS m analysis so that candidates for a composition formula of a target substance is narrowed down in the n−1 stages; and a data processor, the data processor including a) a candidate refiner for deducing the composition formula of the target substance, based on the data obtained by each MS m analysis; b) an information creator, which is a means for creating information to display a composition formula candidate deduced by the candidate refiner, for creating display information so that a composition formula candidate which has passed a refinement and a composition formula candidate excluded in the refinement are displayed on a same display in a visually discriminable manner.