Gas Chromatography - Mass Spectrometry
GC-MS (Gas Chromatography-Mass Spectrometry) analyzes an oil by taking a small sample and volatilizing it into a gas using increasing heat so it can move through a special column. This is the Gas Chromatography portion of GC-MS. While moving through the column, the molecules naturally separate based on their weight, polarity, and size. This separation happens as lighter, smaller components travel faster than the heavier, bulkier components through the column. As these components exit the column, they are recorded as peaks on a chromatogram. The sample components then move to the Mass Spectrometer, where they are hit with 70 eV of electrons. These electrons break the sample into fragments and ions, which move through an accelerator. These fragments and ions are then measured and a spectrum is produced.
The resulting graph from this process shows the peaks of each component in their proportionality to the sample. A reference library of components can automatically identify the peaks as each component present.
Most labs run a GC-MS for 20 minutes, however, we have found that such a short run fails to detect all of the heavier components. APRC runs a GC-MS for nearly two hours in order to record all of the components. Once the run is finished, a chemist is able to analyze the resulting graph to determine if an oil meets the standards in its category.