Mass spectrometry (MS) became an essential tool used by many prominent leaders of the biological research community and the importance of MS to the future of biological research is now clearly evident as in the fields of Proteomics and Metabolomics, especially when coupled to chromatographic separation.Fourier Transform Ion Cyclotron Mass Spectrometry (ICR-FT/MS) is an ultrahigh resolution MS system that allows new approaches in the analysis of complex mixtures.The mass resolution at high fields (< 200 ppb) allow to assign the element composition (C, H, O, N, S...) to each of the obtained mass peaks in a high dynamic range and thus to give a description in terms of molecular composition out of a mixture of up to 15000 signals at S/N 2.