TRENDS

Abstract Metabolomics has emerged as the latest of the so-called “omics ” disciplines and has great potential to provide deeper understanding of fundamental biochemical processes at the biological system level. Among recent technological developments, LC–HRMS enables determination of hundreds to thousands of metabolites over a wide range of concentrations and has developed into one of the most powerful techniques in non-targeted metabolomics. The analysis of mixtures of in-vivo-stable isotopic-labeled sam-ples or reference substances with un-labeled samples leads to specific LC–MS data patterns which can be systematical-ly exploited in practically all data-processing steps. This includes recognition of true metabolite-derived analytical fea-tures in highly complex LC–MS data and characterization of the global biochemical composition of biological samples. In addition, stable-isotopic labeling can be used for more accu-rate quantification (via internal standardization) and identifi-cation of compounds in different organisms