This review presents an overview of the dynamically developing field of mass spectrometry-based metabolomics. Metabolomics aims at the comprehensive and quantitative analysis of wide arrays of metabolites in biological samples. These numerous analytes have very diverse physico-chemical properties and occur at different abundance levels. Consequently, comprehensive metabolomics investigations are primarily a challenge for analytical chemistry and specifically mass spectrometry has vast potential as a tool for this type of investigation. Metabolomics require special approaches for sample preparation, separation, and mass spectrometric analysis. Current examples of those approaches are described in this review. It primarily focuses on metabolic fingerprinting, a technique that analyzes all detectable analytes in a given sample with subsequent classification of samples and identification of differentially expressed metabolites, which define the sample classes. To perform this complex task, data analysis tools, metabolite libraries, and databases are required. Therefore, recent advances in metabolomics bioinformatics are also discussed.

/pdf/mass-spectrometry-based-metabolomics-4bkxmsksad.pdf

Mass spectrometry-based metabolomics.

An overview is presented of gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS), the two major hyphenated techniques employed in metabolic profiling that complement direct 'fingerprinting' methods such as atmospheric pressure ionization (API) quadrupole time-of-flight MS, API Fourier transform MS, and NMR. In GC/MS, the analytes are normally derivatized prior to analysis in order to reduce their polarity and facilitate chromatographic separation. The electron ionization mass spectra obtained are reproducible and suitable for library matching, mass spectral collections being readily available. In LC/MS, derivatization and library matching are at an early stage of development and mini-reviews are provided. Chemical derivatization can dramatically increase the sensitivity and specificity of LC/MS methods for less polar compounds and provides additional structural information. The potential of derivatization for metabolic profiling in LC/MS is demonstrated by the enhanced analysis of plant extracts, including the potential to measure volatile acids such as formic acid, difficult to achieve by GC/MS. The important role of mass spectral library creation and usage in these techniques is discussed and illustrated by examples.

http://www.univie.ac.at/mosys/Teaching_Downloads_PP_MetabolomicsDepartment/halket_et_al_jxb_2005.pdf

Chemical derivatization and mass spectral libraries in metabolic profiling by GC/MS and LC/MS/MS

Comprehensive two-dimensional gas chromatography: a powerful and versatile analytical tool.

Data analysis methods are essential to transform chromatographic data into useful information. There is an ongoing evolution of data analysis methods as increasingly challenging applications need to be addressed, instrumentation advances occur, separation speeds increase, data dimensionality increases, and growing volumes of data are collected. As the traditional data analysis methods have been covered in prior chapters, this chapter focuses primarily on advanced data analysis methods known as chemometrics. Chemometrics are mathematical methods that glean useful information from chemical data, especially large volumes of complex data that are not amenable to traditional or manual analysis. Chemometrics fill several analytical roles. First, the ability to identify and quantify analytes at extremely low chromatographic resolution can be provided. Second, pattern recognition and classification are often implemented, where a chromatogram provides a chemical fingerprint. Third, groups of compounds may be quantified in concert using chemometric methods. Finally, another area of broad interest is retention prediction for separation optimization.

Data Analysis Methods

Mass Spectrometry Strategies in Metabolomics

Recent developments in the application of comprehensive two-dimensional gas chromatography.

We review the literature on comprehensive two-dimensional gas chromatography (GC × GC), emphasizing developments in the period 2003–2005. The review opens with a general introduction, the principles of the technique and the set-up of GC × GC systems. It also discusses theoretical aspects, trends in instrumentation, column combinations, and detection techniques – notably mass spectrometric detection. We devote attention to a wide variety of applications and to analytical performance.

Recent developments in comprehensive two-dimensional gas chromatography (GC × GC): I. Introduction and instrumental set-up

Simple, non-moving modulation interface for comprehensive two-dimensional gas chromatography

We review the literature on comprehensive two-dimensional gas chromatography (GC × GC), emphasizing developments in the period 2003–2005. The review opens with a general introduction, the principles of the technique and the set-up of GC × GC systems. It also discusses theoretical aspects, trends in instrumentation, column combinations, and detection techniques – notably mass spectrometric detection. We devote attention to a wide variety of applications and to analytical performance. Part II discusses the key aspects of modulation and the various modes of detection.

Mohamed Adahchour

Papers

Recent developments in the application of comprehensive two-dimensional gas chromatography.

Recent developments in comprehensive two-dimensional gas chromatography (GC × GC): I. Introduction and instrumental set-up

Simple, non-moving modulation interface for comprehensive two-dimensional gas chromatography

Recent developments in comprehensive two-dimensional gas chromatography (GC x GC) II. Modulation and detection

Recent developments in comprehensive two-dimensional gas chromatography (GC x GC) III. Applications for petrochemicals and organohalogens