The physical states of the mobile and stationary phases give rise to four basic types of chromatography: gas-liquid chromatography (GLC), gas-solid chromatography (GSC), liquid-liquid chromatography (LLC), and liquid-solid chromatography (LSC). Of the four basic types of chromatography, the two gas systems are independent and not subject to subdivisions. Thus the terms "gas-liquid chromatography" and "gas-solid chromatography" adequately identify the techniques involved. The liquid systems are not as easily described and are not mutually exclusive, which can lead to considerable confusion.
