Gas chromatography–mass spectrometry (GC/MS)-based metabolomics profiling methods have been developed and used for plant metabolite profiling since the 1980s. Only during the past few years has the technology been more widely used for metabolomics studies in animals and humans with the aim of toxicology and biomarker discovery, disease diagnosis and classification.
GC-MS is ideally suited and has traditionally been used for analysis of nonpolar analytes like synthetic organic compounds and hydrophobic natural products. Nonpolar compounds have to be derivatized to make them amenable to analysis by GC-MS. This means that care has to be taken to ensure that the variability inevitably introduced by this preprocessing step is kept to an absolute minimum. Over the past few years, robust sample preparation and analysis methods have been developed, which will be described in this chapter. In addition, a brief introduction to gas chromatography and mass spectrometry will be given for readers who are less familiar with these subjects.
GC-MS is distinctly different from the two other more established analytical methods that are used in metabolomics: nuclear magnetic resonance (NMR) and liquid chromatography (LC)-MS, in that it covers a unique range of analyte polarities. It has been found that the overlap between GC-MS and LC-MS metabolomic profiling data is limited because of the differences in separation and ionization mechanisms.
GC-MS has very high sensitivity and can therefore be used for the analysis of less commonly encountered types of samples that might only be available in minute amounts. Examples for this application area will also be given in this chapter.