Gas chromatography coupled with mass spectrometry (GC-MS / GC-MS/MS)
Gas chromatography-mass spectrometry (GC-MS) is a cutting-edge analytical technique for separating, identifying, and quantifying volatile and semi-volatile organic compounds in a sample with high precision. Widely used for trace analysis, GC-MS has established itself as a benchmark method in the pharmaceutical, cosmetic, food, environmental, and materials sectors.
What are GC-MS and GC-MS/MS?
GC -MS (Gas Chromatography – Mass Spectrometry) combines two complementary analytical steps:
- chromatography (GC) separates the different constituents of a mixture based on their volatility and their interactions with a chromatographic column.
- Mass spectrometry (MS) allows each separated compound to be identified by measuring its mass/charge ratio (m/z) after ionization, and by analyzing its fragmentation spectrum .
Each compound generates a characteristic signal, compared to reference spectral libraries for reliable identification, even at trace levels.
GC-MS/MS (or tandem MS version adds a controlled ion fragmentation step, providing increased specificity and enhanced sensitivity , particularly useful for complex matrices or compounds at very low concentrations.
How the GC-MS method works
GC-MS analysis follows several successive steps:
- Injection and vaporization : The sample is injected into the heated injector and immediately vaporized.
- Chromatographic separation : compounds migrate in a capillary column according to their volatility and affinity with the stationary phase.
- MS source ionization : Separated compounds are ionized (often by electron impact – EI) to form characteristic fragments.
- Mass spectrum analysis : Each ion is detected according to its mass/charge ratio (m/z), producing a specific spectrum.
- Identification and quantification : spectra are compared to databases, or processed in SIM mode for targeted and ultra-sensitive detection.
Technical characteristics of GC-MS
- Ultra-sensitive detection : ng/g to pg/g depending on the compounds
- Analysis modes : full scan (qualitative), SIM (targeted quantitative)
- Ionization : electron impact (EI), chemical ionization (CI)
- Spectral database : NIST, Wiley, in-house
- Associated standards : European Pharmacopoeia, USP, ISO, REACH, FCM directives, etc.
- Matrix compatibility : solids, liquids, extracts, films, environmental samples
For which matrices?
GC-MS and GC-MS/MS are suitable for a wide variety of matrices, including those containing volatile or semi-volatile :
Main industrial applications
GC-MS is used in routine analyses , product development and regulatory expertise in many industrial sectors:
Léa Géréec
Technical and scientific advisor
