Patent ID: 7202471

Claim:
A method of mass spectrometry comprising the steps of: separating a mixture into components by a chromatograph; ionizing the separated mixture components and obtaining measurement data from a mass spectrometer; producing a mass chromatogram from the obtained measurement data for a given period; extracting a spectrum from the mass chromatogram; and searching a library holding information about molecular structures of known compounds to thereby perform a qualitative or quantitative analysis of a compound, wherein a total ion chromatogram is obtained from the mass spectrometer, wherein an accumulation mass spectrum close to desired peak tops is extracted from the total ion chromatogram and displayed, wherein a desired mass peak is selected from the displayed accumulation mass spectrum, and wherein another mass chromatogram which is coincident in elution start time, maximum elution time, and elution end time with the mass chromatogram of the selected mass peak is selected out as a mass peak, whereby a mass spectrum of a single component is reconstructed.