Gas Chromatography-Mass Spectrometry: Principles & Applications

Gas chromatography-mass spectrometry, often abbreviated to GCMS, is a well-established analytical technique that combines a unique form of size exclusion chromatography with one of the world???s most sensitive detection technologies.

To date, gas chromatography-mass spectrometry has been employed in a diverse set of applications from detecting illicit drugs to carrying out environmental screening of ecological samples. It also remains the go-to technology for investigating mineral samples obtained by astronaut probes. If there are organic substances to be found on Mars, for instance, scientists are likely to uncover them using gas chromatography-mass spectrometry.

How Does Gas Chromatography-Mass Spectrometry Work?

As mentioned, GCMS is an amalgamation of two distinct techniques: Gas chromatography and mass spectrometry. To understand how GCMS works requires a basic understanding of each underlying technique. We wrote a short overview of gas chromatography in a previous article and would recommend reading that for more in-depth insight.

In short: Gas chromatography uses a microporous stationary medium to separate the compounds of a mobile phase. These compounds elute from the stationary phase at different rates depending on various factors (chemical affinity, molecular weight, etc.), which enables an integrated detector to acquire a full spectrum of the mixture???s chemical composition.

Various detection systems can be coupled to gas chromatographs, but in the case of GCMS, the detector is ??? obviously ??? a mass spectrometer. The concepts of mass spectrometry are likewise fairly complicated, but we will attempt to offer a short overview here, to hopefully explain how gas chromatography-mass spectrometry works.

Mass spectrometry involves the ionization of compounds to determine their chemistry and mass. This is most often carried out using an electron ionizer, which is essentially an exposed electrical filament that bombards the eluent with free electrons, causing them to fragment. Ionized mass from this interaction is then separated based on their characteristic mass to charge ratios and converted into a digital output. The relative intensity of these digital signals is plotted as a mass spectrum, which gives a supremely accurate measure of a sample???s elemental composition down to the sub-parts per million (ppm) range.

Gas chromatography-mass spectrometry subsequently couples the end of a GC column to some form of ionizer in a mass spectrometer. With unprecedented accuracy and increasing user flexibility, GCMS systems are increasingly trusted in a wide range of critical application areas.

Gas Chromatography-Mass Spectrometry with Lambda

Lambda is a specialist supplier of advanced analytical technologies for an array of market areas. If you would like to speak with a sales representative about using gas chromatography-mass spectrometry in your sector, simply contact us today.