The normal phase chromatography is a type of HPLC chromatography. In which the mobile phase is moderately polar and the stationary phase is used to separate the analytes, which is freely soluble in moderate solvents. Less polar molecules in NP-chromatography elute first than the polar molecules. The retention time (RT) of the analyte is reduced by the use of more polar solvents in the mobile phase. Normal phase chromatography is preferable to separate molecules that differ in functional groups.
The advantages of normal phase chromatography are as follows.
- The non-polar solvent can be used to dissolve a sample.
- It is perfect for isomer isolation, and very hydrophilic or hydrophobic molecules.
- NP-chromatography is the most preferred technique for column chromatography.
- Using low viscosity solvents it can have higher flow rates.
- It can be used for compounds that can decompose in water.
The disadvantages of normal phase chromatography are as follows.
- It is not suitable for the analysis of a wide range of compounds.
- Gradient elution is not possible due to solvent de-mixing.
- Formation of bubbles and evaporation can cause by lower boiling point solvents.
- It is difficult to control the strength of the solvent.
- The retention time of components can be variable.