Fig. 1
Most abundant urine metabolites and their concentration ranges in physiological conditions. Concentration ranges of the 260 most abundant metabolites in urine as determined by liquid chromatography coupled with mass spectrometry (LC-MS), NMR spectroscopy, gas chromatography with mass spectrometry (GC-MS), inductively coupled plasma mass spectrometry (ICP-MS), and high-performance liquid chromatography (HPLC)1. a Metabolites are sorted according to their mean absolute concentration values in urine. In the literature, urine metabolite concentrations are reported relative to creatinine1. Consequently, the absolute values were calculated by multiplying the reported minimum and maximum relative concentration of each metabolite by the minimum and maximum of creatinine, respectively. In this way, the reported ranges extend somewhat more with respect to the physiological ranges. Green bars and blue bars indicate the active metabolites and the inorganic ions (respectively) used to prepare the mother solutions of the artificial urine samples. Orange bars indicate the passive metabolites that were only spiked in the mother solutions. b Enlargement of the first 136 urine metabolites, with mean concentration value >30 μM. Among these metabolites, we have selected 47 (green and blue bars) as a part of the active metabolites, taking into account not only their high abundance, but also their high occurrence in urine1. Four additional inorganic ions (rubidium, lithium, aluminum, and zinc) were included among the active metabolites because they affect the metabolite signal chemical shifts even if they are in low abundance
