Imaging mass spectrometric data processing method and imaging mass spectrometer

摘要

Compressed data of mass spectra obtained at respective measurement points and normalization coefficients for XIC normalization or the like are stored in a memory (21). When a normalized imaging graphic at a specific m/z value is to be displayed, a data decompression processor (23) reads the minimally required set of compressed data from the memory (21) and restores the intensity value corresponding to the m/z value at each measurement point. A normalizing calculation processor (29) reads an XIC normalization coefficient corresponding to the m/z value from the memory (21) and corrects the intensity values at each measurement point by multiplying those values by the coefficient. An imaging graphic creation processor (27) assigns a display color to each of the corrected intensity values to create an imaging graphic, and displays the imaging graphic on the screen of a display unit (6). According to this method, even in the case of sequentially displaying imaging graphics while changing the normalization condition, those graphics can be displayed at high speeds if the normalization coefficients are previously calculated and stored.

主权项

1. An imaging mass spectrometric data processing method for processing imaging mass spectrometric data collected by performing a mass spectrometry on each of a plurality of measurement points on a sample, the imaging mass spectrometric data including a plurality of sets of mass spectrum data, where each set is composed of a one-dimensional array of ion-intensity values, related to spatial position information of the measurement point, and the method comprising:
a) a compression step, in which a compression process is performed on the imaging mass spectrometric data of each measurement point according to a predetermined algorithm, and the obtained compressed data are stored in a first storage area of a storage unit; b) a normalization coefficient preparation step, in which a normalization coefficient for normalizing the intensity values in the imaging mass spectrometric data of each measurement point according to a predetermined criterion is calculated for each measurement point, and the calculated result is stored in a second storage area of the storage unit; c) a normalized spectrum creation step, in which at least one of an accumulated mass spectrum, an average mass spectrum or a maximum intensity mass spectrum composed of maximum intensity values extracted at each mass-to-charge ratio, of normalized mass spectra obtained at a plurality of designated or specific measurement points, is calculated as a normalized mass spectrum, using the compressed data of the intensity values corresponding to each measurement point stored in the first storage area of the storage unit, the normalization coefficient of each measurement point stored in the second storage area of the storage unit, and the spatial position information of the measurement points; and d) a normalized graphic creation step, in which an imaging graphic showing a two-dimensional distribution of the normalized intensity values for a designated or specific mass-to-charge ratio or mass-to-charge-ratio range is created, using the compressed data of the intensity values corresponding to each measurement point stored in the first storage area of the storage unit, the normalization coefficient of each measurement point stored in the second storage area of the storage unit, and the spatial position information of the measurement points.