This instrument class includes gas and liquid separation techniques. All chromatography instruments incorporate the following: a sample-introduction port of some type; a delivery system for a mobile phase carrier which moves the sample through the system; a stationary phase, which may be held within a column, a capillary and one or more detectors that detect changes in the nature or amount of the material emerging from the column. The different types of stationary phases—liquid, gas, or supercritical fluid, etc.— contribute to the names of the techniques.