In: Chemistry
When using radial paper chromatography to separate ink pigments, does the least soluble or most soluble pigment travel the furthest distance? The solvent is water.
Chromatography is probably the most useful method of separating
organic compounds for identification or purification.
There are many different types of chroma tography but most work on
the principle of absorbance. The two important components of
chromatography are the absorbent and the eluent. A good absorbent
is usually a solid material that will attract and absorb the
materials to be separated.
Paper, silica gel, or alumina are all very good absorbents. The
eluent is the solvent which carries the
materials to be separated through the absorbent.
Chromatography works on the principle that the compounds to be separated are slightly soluble in the eluent and will spend some of the time in the eluent (or solvent) and some of the time on the absorbent. When the components of a mixture have varying solubilities in the eluent, they can then be separated from one another.
The polarity of the molecules to be separated and the polarity of the eluent are very important. This affinity for the eluent versus the absorbent is what separates the molecules. In paper chromatography, the absorbent is the paper itself. The eluent can be any number of solvents; in this lab, the eluent is water. Water is a very polar molecule.
The polarity of the eluent is important in paper chromatography
since a small change in
polarity can dramatically increase or decrease the solubility of
organic molecules. The organic pigments in the inks, which will
be