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Gas Chromatography/Mass Spectrometry

Mass Spectrometry

  1. Peter T. Palmer

Published Online: 15 SEP 2006

DOI: 10.1002/9780470027318.a6008

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Palmer, P. T. 2006. Gas Chromatography/Mass Spectrometry. Encyclopedia of Analytical Chemistry. .

Author Information

  1. San Francisco State University, San Francisco, USA

Publication History

  1. Published Online: 15 SEP 2006

Abstract

Gas chromatography/mass spectrometry (GC/MS) is perhaps the most widely used analytical technique for the analysis of complex mixtures. The power of this technique stems from the “marriage” of two powerful techniques into a hyphenated method. Gas chromatography (GC) is used to separate the components of a mixture based on their differing affinities for the stationary phase on the column. Mass spectrometry (MS) serves not only to detect and quantify the various species eluting off the column but also provides definitive information as to their identity. The most common GC/MS instruments employ a gas chromatograph with a split/splitless injector, capillary column, and either a quadrupole or quadrupole ion trap as a mass analyzer. A high degree of automation and a powerful data system are required for handling the large amounts of three-dimensional (3-D) data (time, mass-to-charge ratio, and intensity) that can be generated. The technique typically requires that the analytes in question have sufficient volatility to be amenable to GC. It is very sensitive, with detection limits typically in the picogram or even sub-picogram range. It can be highly selective and allows for incredible flexibility with respect to the type and quality of the mass spectral data; the user may choose from a number of ionization modes and scan modes, and control mass range and mass resolution, and many other experimental parameters. Analysis speeds are relatively slow due to the time required for adequate chromatographic separation, but can be reduced to an order of a few minutes using fast GC techniques. GC/MS instrumentation is usually intended for benchtop operation in the laboratory, although a number of field-portable instruments have been developed. The technique requires significant user expertise, knowledge of various means for compound identification and quantitation, and instrument tuning, maintenance, and upkeep.