Gradient separations in normal phase are much more complicated because of UV cutoff variation as well as differences in compressability of common hydrophobic solvents, which would have an effect on flow rate. Reverse phase chromatography also has the advantage of being able to use pH selectivity to improve separations.

Why is reverse phase chromatography extensively compared to normal phase chromatography?

Gradient separations in normal phase are much more complicated because of UV cutoff variation as well as differences in compressability of common hydrophobic solvents, which would have an effect on flow rate. Reverse phase chromatography also has the advantage of being able to use pH selectivity to improve separations.

What is meant by normal phase chromatography?

Definition: A separation method where the components are distributed between two phases, one of which is stationary and polar, while the other is non-polar and moves in a definite direction.

Why is normal phase chromatography used?

It is great when a compound is too hydrophobic or hydrophilic for reverse-phase HPLC. It can also be used for isomer separation, if the sample injection solvent is non-polar, or if recovery in non-polar solvents is desirable. In normal phase chromatography, the stationary phase is polar, usually using silica.

What is reverse phase chromatography used for?

Reversed-phase chromatography is the most common HPLC separation technique and is used for separating compounds that have hydrophobic moieties and do not have a dominant polar character (although polarity of a compound does not exclude the use of RP-HPLC).

What is the difference between Hilic and normal phase?

HILIC is a variation of normal phase chromatography. The major differences between HILIC and NP are the composite of the mobile phase and the mechanism of separation. Common NP chromatography uses 100 % organic mobile phases while HILIC uses organic mobile phases that are water miscible.

What is the difference between HPLC and RP HPLC?

The key difference between reverse phase and normal phase HPLC is that the reverse phase HPLC uses a nonpolar stationary phase and a polar mobile phase whereas the normal phase HPLC uses a polar stationary phase and a less polar mobile phase.

What is meant by reverse phase?

Reversed-phase chromatography is a technique using alkyl chains covalently bonded to the stationary phase particles in order to create a hydrophobic stationary phase, which has a stronger affinity for hydrophobic or less polar compounds.

Is TLC normal phase or reverse phase?

Normal-phase thin-layer chromatography (NP-TLC) is an established method for the separation of all major phospholipid classes according to the different polarities of the head groups. In contrast, reversed-phase (RP)-TLC is much less frequently used for this purpose.

What are the differences between reverse phase HPLC and normal phase HPLC?

The main difference between normal phase and reverse phase chromatography is that normal phase chromatography has a very polar stationary phase and a non-polar mobile phase whereas reverse phase chromatography has a non-polar stationary phase and a polar mobile phase.

Is HILIC reverse phase?

HILIC is sometimes called “reverse reversed-phase” because water is the “strong” or eluting solvent, which is the opposite of reversed-phase LC, where water is the “weak” solvent (Figure 1).