What Is Gas Chromatography?

Gas Chromatography (GC) is a general technique used in the analysis of volatile and semi-volatile organic compounds.  This technique relies on heating a sample in the presence of a carrier gas and a stationary phase.  The analyte is separated from the sample and other solvents based on its relative affinity for the two phases.  Once the analyte elutes from the column, one of many detectors can be used to measure it.

Detectors

Detectors are chosen based on their overall applicability to detect a given analyte or class of analytes.    For example, a very common GC detector is the Flame Ionization Detector (FID), which relies on ionizing the analyte in a hydrogen flame.  Many organic solvents respond to this detector so it is considered versatile, but some solvents (such as carbon tetrachloride) exhibit very weak signal when analyzed by GC-FID.  Other detectors, such as an Electron Capture Detector (ECD), are more suitable for the analysis of  compounds in the class of halogenated organics.

Another versatile detector coupled to GC’s is the Mass Spectrometer.  This detector gives signal for a wide range of compounds along with the benefit of providing a mass spectral scan of the analyte and other compounds in the sample.

Cornerstone provides the following GC Detectors:

• Thermal Conductivity Detector (TCD)
• Flame Ionization Detector (FID)
• Mass Spectrometer (MS)

 Our TCD Injection Methods:

• Liquid
• Headspace
• SPME

Our TGA Oven Range:

Cryogenic to 450

• Restek
• Grace
• Agilent

Thermo columns are all on hand.