Gas chromatography is a method for the separation and analysis of complex mixtures of volatile organic and inorganic compounds (1:666). Most compounds with boiling points less than 250oC (480oF) can be analyzed using this technique. This paper will describe the apparatus used for gas chromatography, the principles on which it works, how a thermal conductivity detector works in gas chromatography, and whether or not it can be used with a sample of potassium t-butoxide.
General Principles of Gas Chromatography
There are two types of gas chromatography: gas-liquid chromatography, where the sorbent is a nonvolatile liquid called the stationary liquid phase, coated as a thin layer on an inert, granular solid support; and gas-solid chromatography, where the sorbent is a granular solid of large surface area (1:666). The moving gas phase, called the carrier gas, is an inert gas such as nitrogen or helium. The gas flows through the chromatographic column packed with the sorbent. The solution being chromatographed divides itself between the moving gas phase and the sorbent, and moves through the column at a rate dependent upon its partition coefficient, or solubility (in the liquid phase in gas-liquid chromatography), or upon its adsorption coefficient on the packing (in gas-solid chromatography), and the carrier gas flow rate (1:666).
Gas-solid is the older of the two forms of gas chromatography, and was originally limited to the separation of permanent gases or relatively nonpolar solutes of low molecular weight. More recent gas-solid adsorption chromatography research has shown considerable progress in decreasing objectionable peak tailing, and thus providing higher separation efficiencies than those that were possible in the past (1:666). Gas-liquid chromatography is more popular, and has more versatility for the separation of a wide range of higher molecular weight compounds because of the large choice of liquid phases a...