# Chromatography questions watch

1. What is the basis of the Thin Layer Adsorption Chromatography (TLC) separation?

Thanks.

(Original post by Revd. Mike)
It's a pretty simple principle, have you googled?
May it be based on for example adsorption, ion exchange, partition, or gel filtiration?

But, what mediums are used in this process?

(Original post by Revd. Mike)
For TLC, the medium used is generally a layer of silica gel or alum or similar, this is the stationary phase. The mobile phase can be any number of solvents depending on the polarity required. Read the wikipedia article to get you started.
The wikipedia article mentions the following:

Thin layer chromatography is performed on a sheet of glass, plastic, or aluminum foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide, or cellulose (blotter paper). This layer of adsorbent is known as the stationary phase.

And, here: http://www.tutorvista.com/chemistry/...ationary-phase, it mentions the following:

The stationary phase can be a solid or liquid supported on a solid, while the moving phase is a liquid or a gas. When the stationary phase is a solid, the basis of separation is adsorption; when the stationary phase is a liquid, the basis is partition.

So, based on that, can we say that the basis of separation may be adsorption if the staionary phase is solid, or partition if the stationary phase os liquid?
2. -When we say liquid chromatography or High Performance Liquid Chromatograpy (HPLC), are we referring to the same thing?

Thanks.
3. Knowing that the retention factor Rf = Distance moved by sugar / Distance travelled by solvent

I have the following questions:

1- In measuring the distance, do we use cm for example? And, is this done starting from the origin line and moving up vertically?
2- Is the distance travelled by the solvent the distance from the origin line to the solvent front (the highest point reached by the solvent)?

If I'm seperating sugars by Thin Layer Adsorption Chromatography (TLC), and have calculated the Rf values for each sugar I have, in addition to recording each sugar's colour, how can I use this information to conclude what is my unkown sugar?
4. Hey, I've merged all of the threads you've made regarding chromatography into one thread. In future, if you have several questions on one topic, it's easier to keep track of everything if you do it in one thread

(Original post by SWEngineer)
-When we say liquid chromatography or High Performance Liquid Chromatograpy (HPLC), are we referring to the same thing?

Thanks.
HPLC is a form of liquid chromatography, but the terms aren't interchangeable. HPLC refers to a specifc set up where the mobile phase is forced through the stationary phase at high pressure, and the eluent is collected through some form of detector.

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