Gas analysis is a method used to obtain a sample of volatile compounds present in the atmosphere or in the vapor phase above a sample in a sealed container. Headspace analysis is one specific method that is defined as the mixture of vapors which exists in equilibrium with a sample held in a closed system. Gas sampling consists of two different types of procedures. These are termed direct gas sampling and gas concentration. Direct gas sampling is an easy procedure, but it is much less sensitive than gas concentration. These techniques will be discussed and their advantages and disadvantages presented. Methods to increase the sensitivity of these techniques including splitless injections, cryofocusing, and temperature of equilibration will also be presented.