Worksheet: Thin-Layer Chromatography
In this worksheet, we will practice describing thin-layer chromatography methods, selecting mobile phases and methods for staining or detecting fractions.
When separating a solid mixture by thin-layer chromatography, which of the following steps is not required?
- AThe solid is dissolved in an organic solvent.
- BMovement of the solvent front is accurately timed.
- CA spot of solution is applied to the plate.
- DThe base of the upright plate is immersed in an organic solvent.
- EMovement of the solute spots is accurately measured.
A reaction mixture is analyzed by thin-layer chromatography before (A) and after (B) a reaction takes place, using a silica TLC plate and a mixture of hexane and ethyl acetate. In the diagram showing the TLC plate, the positions of the separated fractions are marked as spots between the baseline (solid line) and solvent front (dashed line).
Which spot corresponds to the product of the reaction with the highest polarity?
Which spot corresponds to the limiting reactant in this reaction?
Estimate the value of fraction 5, to 1 significant figure.
Which of the following statements about the mobile phase in supercritical fluid chromatography (SFC) is false?
- AIt has the solvent properties of a liquid.
- BIt requires lower pressures than those needed for HPLC.
- CIts mobile phase has the viscosity properties of a gas.
- DIt gives better resolution than GC.
- EIt has densities similar to a liquid.