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Gas Chromatography Mass Spectroscopy (GCMS)

Gas Chromatography Mass Spectroscopy Main Image
Sample GCMS output mass spectrum with peaks of interest identified.

Gas Chromatography-Mass Spectroscopy (GCMS) combines two instrumental systems: a gas chromatograph component where the sample is volatized, followed by a mass spectrometer, which filters the incoming gaseous particles by their mass. This system outputs a quantitative representation of the chemicals present in a sample.


  • Highest sensitivity for identification of trace organic impurities / contaminants
  • Requires minimal sample volume
  • Optimized for organic compound analysis
  • Cost-effective chemical analysis


  • Requires time-intensive data analysis / interpretation
  • Destructive analysis
  • Cannot directly analyze non-volatile, polar, or combustible samples

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Sample Requirements

Example Outputs

Sample GCMS output mass spectrum with peaks of interest identified.

Instruments Used



  • Integrated NIST library search software for analyte identification
  • Inert electron ionization source
  • Temperature Range: 150 to 300 °C
  • High sensitivity: instrument detection limit (IDL) = 18.7 fg
  • Wide Dynamic Range: 4 Orders
  • Wide Mass Range: ~m/z 6,000
  • High Mass Resolving Power: 30,000
  • High Mass Accuracy: to 1 ppm
View Instrument Brochure

How GCMS Works

In the GC component, the sample is vaporized and accelerated with a carrier gas (typically He or Ar) into a chromatographic column, where the sample particles begin to separate based on their variable interactions with the column walls. They are carried onward to pass through an ionizing domain, which imbues the incoming particles with charge.

Finally, the sample ions continue to travel through an electrostatic field, which filters them according to their mass / charge (m/z) ratio. They arrive at a detector which reads out the number of incident particles associated with each mass increment, to produce a spectrum of peaks at the characteristic m/z ratios of all chemical constituents of the sample.

GC-MS is distinct from ICP-MS in that it captures more molecular structure information for organic samples, and can be used to separate and quantify compounds in chemical mixtures.