Gas Chromatography

In gas chromatography, the sample vapor passes through the column and separates into its components — a separation that is governed by the distribution between the mobile and stationary phase. The degree of separation between the sample and the stationary phase is determined by flow rate, the nature of the stationary phase, the surface area exposed to the carrier gas, and the column temperature. Thus, while solvent changes are commonly used in HPLC, GC uses temperature changes to improve separations. As the individual components emerge from the column, the detector obtains a signal and relays the message to the data.

GC regional distribution.

The GC columns may be of two types, packed or capillary. The packed column can accept a larger injection volume, but the capillary column has better separating power. There are a number of different detectors available as a function of the analyte constituent. These include thermal and electrolytic conductivity, flame ionization, electron capture, nitrogen-phosphorous, photoionization, mass selective, infrared, and atomic emissions detectors.

Gas chromatography is very well established in the U.S., western Europe, and Japan where the installed base is extremely large. In fact, North America and Europe combined account for nearly two-thirds of the worldwide gas chromatography demand. However, lower-end GC’s have become ubiquitous in areas such as eastern Europe, China, India, and Latin America.

The foregoing data was extracted from SDi’s Global Assessment Report, 11th Edition. For more information, contact Glenn Cudiamat, VP of Research Services, Strategic Directions International, Inc., 6242 Westchester Parkway, Suite 100, Los Angeles, CA 90045, tel. (310) 641-4982, fax (310) 641-8851, e-mail:cudiamat@strategic-directions.com