Chromatography what is the mobile phase

The stationary phase acts as a constraint on many of the components in a mixture, slowing them down to move slower than the mobile phase. Because of the differences in factors such as the solubility of certain components in the mobile phase and the strength of their affinities for the stationary phase, some components will move faster than others, thus facilitating the separation of the components within that mixture.

Chromatographic Columns Chromatography is an analytical technique that separates components in a mixture. Chromatographic columns are part of the instrumentation that is used in chromatography.

Significantly, paper chromatography and thin-layer chromatography are the two types of planar chromatography. Figure 2: Reverse Phase Gradient Elution. Moreover, the stationary phase always has opposing properties to the corresponding mobile phase of the chromatography. On the other hand, each phase makes interactions with the components of the mixture with similar properties. Thereby, when the stationary phase is non-polar, non-polar components of the mixture tend to stay with the stationary phase while polar components tend to move along with the mobile phase, which is polar as well.

At the end of the chromatography, by sending a solvent gradient with decreasing polarity, the non-polar components staying in the stationary phase can be eluted out. The mobile phase refers to the liquid or gas, which flows through a chromatography system, moving the materials to be separated at different rates over the stationary phase while stationary phase refers to the solid or liquid phase of a chromatography system on which the materials are to be separated or selectively adsorbed.

The mobile phase is the solvent moving through the column while the stationary phase is the substance, which stays fixed inside the column. The mobile phase can be either liquid or gas while the stationary phase is a solid or liquid supported on a solid. Components of the mixture with similar properties to the mobile phase elute earlier while the components of the mixture with similar properties to the stationary phase elute later. A non-polar solvent such as hexane is used in the normal phase while a polar solvent such as methanol is used in the reverse phase in HPLC while a polar stationary phase is used in the forward phase chromatography while a non-polar stationary phase is used in the reverse phase.

Based on the type of mobile phase, there are two types of chromatography; liquid chromatography and gas chromatography, while based on the type of stationary phase, there are two types of chromatography; column chromatography and planer chromatography. The mobile phase is the type of medium, which passes through the column, eluting components of the mixture with similar properties to that of the mobile phase.

Separation by chromatography produces a chromatogram. A paper chromatogram can be used to distinguish between pure and impure substances:. A paper chromatogram can also be used to identify substances by comparing them with known substances. Two substances are likely to be the same if:. In this chromatogram, the brown ink is made of a mixture of the red, blue and yellow inks. This is because the spots in the brown ink have travelled the same distance and have the same R f value as the reference inks.

This distance a spot travels is partly dependent upon the time it is left in the solvent. This distance travelled compared with the distance travelled by the solvent is the same for a particular substance.