Patent ID: 8420406

Claim:
A method for analysing the metabolites of a first biological sample which comprises quantitatively determining at least 50 metabolites in said first sample in a way that said quantitative determination resolves isotopic mass differences within each metabolite, said method comprising a) taking a first biological sample from cells which have been maintained under conditions allowing the uptake of an isotopically labeled metabolizable compound in which substantially all atoms of a given element are isotopically labelled so that the metabolites in said cells are saturated with the isotope with which said metabolizable compound is labeled, wherein the proportion of the label-isotope of at least 50 metabolites of the biological sample is increased to at least 80% of the total of all isotopes of the element; (b) combining said first biological sample with a second biological sample in which the metabolites are not isotopically labelled or are isotopically labelled differently from the first biological sample; (c) separating the metabolites in the samples chromatographically; (d) quantitatively determining at least 50 of the metabolites separated in (c) by mass spectrometry; (e) obtaining for each quantitatively determined metabolite a matrix of (i) chromatographic retention time, (ii) mass, and (iii) signal strength; (f) calculating for each quantitatively determined metabolite of the first and the second sample an isotopomer ratio (ITR) on the basis of the measured signal strengths; wherein the at least 50 metabolites comprise sugars, sugar alcohols, organic acids, amino acids, fatty acids, vitamins, sterols, phosphates, polyamines, polyols, nucleosides, adenine, ethanolamine, nicotinic acid, uracil and/or urea.