What is a Gas Chromatograph?

Specifically developed to help chemists separate and analyze vapor-phase compounds, gas chromatography (GC) is now one of the cornerstone techniques of both analytical and preparative chemistry. The instrument used to carry out these separations is, unsurprisingly, known as a gas chromatograph. Most GC systems feature a degree of modularity, given that test parameters require several interconnected components including an injector, vaporizer, column, and detector.

The term gas chromatograph may refer to the entire GC array, from the syringe to the analytical software. Occasionally, it is used synonymously with the graphical output typically known as a gas chromatogram. For the purposes of this article, we will consider all the essential hardware as part of the main apparatus of a typical gas chromatograph.

Components in a Gas Chromatograph

The first component in a typical GC system is the injector, or syringe, which is used to introduce small volumes of sample material into the machine. Various column inlets exist, and the type used depends on the GC method.

The simplest is probably the split/splitless injector which directly inserts sample material through a septum into a heated chamber, where it is vaporized carried through the system. More complex inlets include headspace sampling systems that extract samples directly from the unused volume at the top of a sealed container.

After the injector is the heating chamber, which is typically a small format with a temperature range of approximately 45° - 200°C. Few GC applications require greater thermal capabilities to properly vaporize samples.

The heart of any gas chromatograph, as with all forms of chromatography, is the column. This thin metal tube is tightly packed with a microporous media that reacts with gas-phase molecules passing through in the continuous flow of inert carrier gas. Different molecules elute through the column at different rates depending on their specific physicochemical properties.

Lastly, a gas chromatograph features some form of the detector to monitor the elution of compounds as a function of concentration and time. Mass spectrometry (MS) is the preferred method of generating detailed gas chromatograms due to its exceptional versatility and ??? typically ??? wide mass range.

Using these systems, analysts can reliably and automatically separate analytes into their components and identify the individual species as well as their relative concentrations.

Gas Chromatography-Mass Spectrometry with Lambda

At Lambda Advanced Technology, we offer high-performance instrumentation manufactured by experts in analytical and preparative chemistry. Among our core product offering is a catalog of gas chromatographs which can be configured to your application, with the basic system including a standard detector and a portable, field-ready system coming with a built-in MS detectors for ease of usability and accuracy, wherever you are carrying out your tests. If you would like to learn more, simply contact a member of the team today.