1. Untargeted metabolite profilingUp to 3000 putative metabolites can be detected using a combination of selected untargeted analytical techniques. Untargeted approaches can cover many classes of metabolites and thus provide broad information about the metabolic state of the analysed samples. However, only a fraction of the detected compounds will be automatically identified or annotated.2. Targeted metabolite profiling This refers to the analysis of specific compound classes, e.g. amino acids and amines, fatty acids, eicosanoids, and hormones. Using LC-QqQMSMS and GC-QqQMSMS in multiple-reaction-monitoring (MRM) mode up to 100 selected compounds can be detected and measured in a single analysis. The advantages of targeted approaches are their selectivity and accuracy. 3. Functional group-specific metabolite profiling This refers to advanced chemical derivatisation and detection strategies to analyse compound-specific structures of both known and unknown compounds. Such strategies can profile, for example, primary and secondary amines, aldehydes, and carboxylic acids.