Why does the spot need to be above the level of the solvent?

The start line above the solvent level allows the solvent to move past the start line, carrying the dissolved samples along with it.

What is the importance of having the spot of plant extract above the surface of the solvent when the chromatography paper is placed in the glass vial?

The solvent is use to draw the photosynthetic pigments up through the chromatography plate. The spot needs to be above the surface of the solvent so that the pigments travel up the plate and don’t just dissolve out into the solvent in the vial.

Why is it important to keep the spots applied to TLC slide for chromatography as small as possible?

keeping small spots on your silica plate (or whatever your immobile phase is) will allow for greater resolution between the spots allowing for more accurate Rf calculations and solvent separation/preparation if using to isolate a compound in a mixture.

Why is it important for the sample spots applied to the TLC plate to be above the level of the solvent when it is placed in the beaker?

The solvent level has to be below the starting line of the TLC, otherwise the spots will dissolve away. Non-polar solvents will force non-polar compounds to the top of the plate, because the compounds dissolve well and do not interact with the polar stationary phase.

Why is a small spot of pigment needed on the TLC plate?

Why might not all of the amino acids known to be present in the mixture have appeared on your chromatogram? Why is a small spot of pigment needed on the TLC plate? Use a different solvent and/or a different stationary phase, this means pigments which may have run together will separate out.

Why is a small spot needed on the TLC plate?

Why is a small spot of pigment needed on the TLC plate? Use a different solvent and/or a different stationary phase, this means pigments which may have run together will separate out.

Why is it recommended to spot the analyte on the TLC plate in a position that it will not be immersed in eluent solvent?

The reason is that the plate will be immersed in the eluting solvent to effect the separation, and the eluting solvent should not touch the spots when the separation begins.

Does a single spot on a TLC plate guarantee a single substance Why or why not?

Does a single spot on a TLC spot guarantee a single substance. Why or why not?!!! No ; pure’ must see 1 spot but if its 1 spot it is not necessary pure. TLC is typically used to determine the correct adsorbent and solvent for column chromatography.

Which direction should the substances travel in paper chromatography?

You also want the substances to “travel” in one direction. If the spot is in the solvent, it will travel in all directions. If the spot is above the solvent, it will only travel upwards. Why must you cover a beaker using a lid during paper chromatography?

Why is it necessary to apply the spot above the solvent?

Hire in-demand talent to keep projects moving. Originally Answered: In a paper chromatography experiment why is it necessary to apply the spot of the mixture to be analyzed above the level of the solvent? It works by the fact that the solvent migrates up the paper by capillary action. This upward motion carries the sample with it.

What is solvent front in chromatography?

Solvent front is the the furthest point reached by the solvent in chromatography. For example, if one component of a mixture travelled 9.6 cm from the base line while the solvent had travelled 12.0 cm]

What happens if the beaker is not covered during chromatography?

Typically the solvent (or solvent mixture) used for the chromatography is rather volatile. So, it is likely that the entire reservoir of solvent will evaporate prior to the completion of the chromatography if the beaker isn’t properly covered.