GC and MS – How does it work?
Chromatography is the separation of a mixture of compounds into individual components. There are three major steps involved with separating and identifying components of a mixture using a GC. They are:
- Injecting a sample into the GC. (This takes place at the inlet.)
The sample is injected into the GC and vaporized with high heat to separate the sample into its individual molecules. These molecules are then mixed with an inert gas at a certain ratio to carry the sample through the column. GC columns vary depending on the application, as their length, diameter, phase properties, and film thickness can all affect how well the individual molecules separate.
- Separating the sample into individual components. (This takes place inside the column in the oven.)
As the molecules travel throughout the column, some of the molecules may travel faster or slower as they are pushed along, depending on their affinity for the column properties. As the molecules leave the end of the column they will come out at different times (known as the retention time) where they encounter the MS.
- Detecting what compounds were in the sample. (This is done in the detector.)
The MS takes the molecules from the GC and bombards them with a beam of electrons so they turn into ions, in a process called ionization. This stream of ions is then shot across an electric field where the ions will accelerate differently based on their electric charge. These then pass through a magnetic field where the ions will bend differently based on their electrical charge and molecular weight. Lighter and more positively charged ions will bend more, and heavier and more negatively charged ions will bend less. A detector then records the spectrum which takes in the information of the charge and molecular weight for each ion, and based off this pattern it identify the molecules in the sample.
GC/MS is a very powerful tool that can identify if a particular chemical should or shouldn’t be in your sample. It can also provide insight into degradation of compounds and ensure that our product has everything that you want in it, and nothing that you don’t want in it.
Dynalene employs an Agilent 7890 Gas Chromatograph equipped with a FID (Flame Ionization Detector) and Mass Selective Detector (MSD) to analyze volatile and semi-volatile components in various sample matrixes. With our expertise in Gas Chromatography Method Development we can analyze a broad range of sample types including volatiles, impurities, contaminants, hydrocarbons, glycols, fatty acids, flavors, and fragrances. We can also develop a custom GC or GC/MS method for your unique analysis needs.