Gas Chromatography

Gas chromatography (GC) is a common technique used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. GC is typically used for separating the different components of a mixture, improving the purity of a particular substance, or identifying a particular compound. GC is a ubiquitous technique, and the various GC instruments available are designed to achieve every requirement of the technique.

Thermo Fisher Scientific has developed an innovative gas chromatography (GC) method for the determination of polychlorinated biphenyls (PCBs) in mineral insulating oil using solid phase micro extraction (SPME) and gas chromatography with an electron capturedetector (ECD).

In 1964, University of Utah chemistry professor J. Calvin Giddings enunciated a theoretical platform, “unified separation science,” that could confer the resolving power of GC to LC. Giddings’ model combined the higher mobile phase diffusion and efficiency of GC with LC’s higher selectivity via orthogonal separation modes. His vision has been made a reality through supercritical fluid chromatography (SFC), which uses supercritical or subcritical carbon dioxide as the mobile phase.

“Fun new tools,” particularly in mass detection, have encouraged a new conversation among separation scientists, says Nicholas Hall, national sales director at LECO (St. Joseph, MI). “Every time this occurs, the instrument vendors engage in the equivalent of an arms race, where the battles are fought over specifications— more resolution, greater fragmentation capability.” But the real discussion has recently involved the very nature of chromatography, Hall says. “Just as important as the tool used for detection on the back end is the time and optimization that goes on at the front end.” Thus the resurgence of basic chromatography optimization, the application of solid analytical chemistry, and a focus on chromatography as the optimization of mass spectrometers. “If you have good separation and good sample preparation, and that goes into the MS, then you’re really optimizing the mass spectrometer’s capabilities.”








