Questions to answer before coming to lab turn them in as you

Questions to answer before coming to lab, turn them in as you walk in to lab along with your pre-lab. 1) What is a TLC? 2) What is TLC used for and why? 3) What is the mobile phase? 4) What is the stationary phase? 5) What is the origin? 6) What is the solvent front? 7) How do you calculate the Rf value for a spot? two spots? 8) In your own words, explain numbers (steps) 11 and 12 in the procedure. What is it that you have to do and how?

Solution

1)Thin-layer chromatography (TLC) is a chromatography technique in which a sheet of plastic, aluminium foil, glass which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide (alumina), or other such materials acts like a adsorbant stationary phase and there is a liquid mobile phase.

2)Mainly used for non-volatile mixtures. It is a simple process and is used for various purposes such as finding the number of components in a given sample, by comparing Rf with the standard , you can determine if similar or same components are present in the sample. It is a relatively simpler and comparatively less expensive but quite accurate. Hence it is widely used

3)the mobile phase is the phase of the chromatographic system that carries the components of the mixture to be separated through the stationary medium being used.

4) Stationary phase is the  solid or liquid phase of a chromatography system on which the materials to be separated are selectively held when the mobile phases passes over it

5)origin is the point where you spot the sample on the TLC plate.

6) Solvent front if the furthest point on the TLC plate reached by the mobile solvent phase

7) The Rf value is the ratio of the distance moved by the solute which is being tested and the distance moved by the the solvent along the paper, where both distances are measured from the common Origin point. For the second spot, the same procedure is follwed