GC-MS analysis

What is GC-MS used for?

GC-MS and its high-sensitivity version, GC-MS/MS, are commonly used to screen different types of samples for volatile and semi-volatile organic contaminants, such as polycyclic aromatic hydrocarbons (PAH), phthalates, and pesticides. Applications for which Measurlabs offers GC-MS analyses include the following:

• NIAS testing of food contact materials, which involves screening the sample for non-intentionally added contaminants without prior information about which compounds are present.

• Chemical characterization of substances released from medical devices (extractables & leachables testing).

• Phthalates analysis of toys, food packaging, and consumer products.

• Printing ink set-off testing to measure the concentration of chemicals transferred to the food contact side of printed articles during storage.

• Volatile organic compound (VOC) screening of water and other environmental samples.

• PAH analysis of food, water, paper, plastics, textiles, and rubber.

• Various food industry quality control analyses, including fatty acid profile determination, dioxin and PCB screening, and ethylene oxide residue testing.

As GC-MS is an exceptionally versatile method, the above are just some examples of popular applications. Do not hesitate to contact us to discuss your analysis needs.

How does the method work?

In GC-MS, the sample is first vaporized and injected into a gas chromatography (GC) column that is coated with a stationary phase. The column is heated, and an inert gas (the mobile phase) carries the sample through it. Compounds with distinct boiling points and polarities interact with the stationary phase in different ways, which leads to their separation and elution from the column at different retention times (RT).

The separated compounds are transferred to a mass spectrometer (MS), where they are ionized and fragmented. The ions are further separated based on their mass-to-charge (m/z) ratios using a magnetic or electronic field. As a result, a mass spectrum, with peaks corresponding to different compounds, is generated. By comparing the data on retention time and (m/z) ratios to existing standards, it is possible to identify and quantify compounds present in the sample.

Suitable samples for GC-MS

GC-MS is well suited for detecting various types of molecules in a wide variety of sample matrices. A requirement for GC-MS analysis is that the compounds in the sample are volatile or semi-volatile so that they can be separated from each other with a gas chromatograph and identified by a mass spectrometer. Many gaseous, liquid, and solid samples are suitable for GC-MS analysis without significant pretreatment. However, the analysis of complex samples or very small sample amounts may require more preparation.

Sample preparation

Gases and very easily volatile samples can be analyzed by collecting the substances of interest with the help of solid-phase microextraction (SPME). Then the compounds can be released into the gas chromatograph for analysis. Low-volatility compounds can be made more volatile through derivatization, where a chemical group, such as methyl or silyl, is attached to the target compound to lower its boiling point.

To examine samples that contain significant amounts of non-volatile matter, a headspace (HS) autosampler can be used. The sampler dispenses gas into the gas chromatograph from the top of the actual test sample, making it possible to analyze volatile compounds originating from non-volatile samples, such as soil or construction materials.

Yet another option is to apply the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method to complex matrices to simplify sample extraction and cleanup. The method is most commonly used to analyze pesticide residues and mycotoxins in food industry samples.

The analysis can also be started with pyrolysis, i.e. breaking the sample through exposure to heat. The resulting py-GC-MS analysis is well-suited for analyzing polymeric materials, lignin, and other complex sample types. A GC-MS setup may also be connected to a thermogravimetric analyzer to analyze the evolved gases that are formed when the sample is heated.

Need an analysis?

Measurlabs offers a comprehensive selection of purity and composition analyses using GC-MS and related methods, such as GC-ECD and GC-FID. Do not hesitate to contact us through the form below to discuss your testing needs. Our experts will get back to you within one business day.