Normal phase columns commonly have stationary phases like CN, Diol, Si or NH2. NH2is the most flexible phase in the normal phase family and can be used in three modes: normal phase, reversed phase and ion chromatography mode (weak anion exchanger). In reversed phase mode it is mainly used for analysis of carbohydrates. CN can be used for a wide range of applications in normal pase mode as well as reversed phase mode (steroids, carbohydrates polar compounds). Diol is an alternative to the silica packing with shorter equilibration time and comparable selectivity. Due to the lower activity of these packings it can be also used for SEC-application. Si for a wide range of different applications, i.e. SEC (size exclusion chromatogra-phy) but also for normal phase HPLC. It is a good choice for analytical and preparative purposes to separate polar compounds.
