Metabolomics and metabolite profiling.

During the last 15 years, metabolomics has emerged as the latest of the so-called “omics” research fields. It deals with the analytical characterization of the metabolome, i.e. the low molecular weight metabolite complement of the biological system under investigation. A wide range of biological systems have benefited from metabolomics studies, from relatively simple microbes to plants and complex multiorganism systems such as mammals. The general goal of most metabolomics studies is to generate a snapshot of the metabolic state of a biological sample and to characterize the changes in the abundances of the measured metabolites arising from natural fluctuations or external, experimental biotic or abiotic perturbations. The topical collection in this issue of Analytical and Bioanalytical Chemistry provides a glimpse of the current activities in metabolomics and metabolite profiling. The articles presented elegantly illustrate that the general concept of metabolomics and metabolite profiling has matured significantly during the last decade and that this recent “-omics” toolbox is widely applied in many scientific disciplines, such as diagnostics of human diseases, biomarker discovery, nutrition, food safety, plant science and microbiology. Most state-of-the-art metabolomics studies use liquid chromatography (LC) or gas chromatography (GC) coupled with mass spectrometry (MS) for metabolite profiling, whereas direct infusion MS, NMR spectroscopy and IR spectroscopy are applied for metabolite fingerprinting without prior separation of the sample constituents. Other techniques such as LC with UV detection can be used to complement these techniques, as successfully illustrated by the contribution on carotenoid profiling of this issue. Moreover, the huge chemical diversity of substances contained in biological samples affords multiple analytical platforms in order to cover a wide range of metabolites. When more than one analytical method is applied, the data, which are derived from the metabolomics platforms, have to be integrated. In the present collection this topic has been addressed in the area of food safety with an untargeted GC–MS-based study using two different methods for the profiling of both volatiles and polar small metabolites for the detection of meat spoilage. Independent of the analytical technique employed, two complementary approaches are widely used in current metabolomics: targeted and untargeted analyses. In the targeted approach a set of predefined known substances is monitored, which usually allows absolute quantification and definite identification when limited to metabolites available Published in the topical collection Metabolomics and Metabolite Profiling with guest editors Rainer Schuhmacher, Rudolf Krska, Roy Goodacre, and Wolfram Weckwerth. R. Schuhmacher (*) :R. Krska Department for Agrobiotechnology (IFA-Tulln), Center for Analytical Chemistry, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria e-mail: [email protected]