Fig. 1.

A general workflow of a comparative metabolomics data analysis which is based on mass peak alignment approach. MSClust receives a mass peak alignment data matrix of size M × S, where M is a number of mass peaks (often tens thousands) aligned across a number of samples profiled S. As the result it produces a reduced data matrix of size C × S, where C a number of putative compounds each represented by a single mass peak (normally a few hundred) aligned across the same number of samples S. Besides, it extracts a mass spectra for each of the compounds C, that in case of GC–MS data is compatible with the NIST MSSearch compound identification software