| abstract |
An object of the present invention is to automatically select an appropriate peak based on an acquired mass spectrum and perform MS 2 analysis as a precursor ion, until the order of MS 2 analysis of ions with low signal intensity comes. In some cases, elution is completed and a sufficient MS 2 spectrum cannot be obtained. An upper limit value UL can be specified together with a lower limit value LL of signal intensity as a mass spectrum peak selection condition. The data processing unit determines whether or not the peak intensity of the peak appearing in the mass spectrum obtained during the LCMS analysis is within the intensity range Ath determined by the upper limit value UL and the lower limit value LL, and excludes peaks that do not enter. The MS 2 analysis is performed with the remaining peaks set to, for example, precursor ions in order of intensity. By appropriately setting the upper limit UL, MS 2 analysis can be performed MS 2 analysis of the low concentration of the component to avoid unnecessary high strength component preferentially. [Selection] Figure 3 |