Fall 2009
Name:
Date:
Experiment 3.7A&B: Solvent and Polarity Effects in Thin-Layer Chromatography
Part A
Solvent Front
(mm)
Solvent
trans-stilbene
(mm)
Rf
vanillin
(mm)
vanillyl alcohol
(mm)
Rf
Rf
Hexane
Ethyl acetate
Acetone
Part B
Solvent System __________________________ Solvent Front (mm)___________
trans-stilbene
vanillin
(mm)
(mm)
Rf
Rf
Unknown Number _________
vanillyl alcohol
Unknown(s)
(mm)
(mm)
Rf
Rf value(s)
Unknown(s) _____________________________________________
Rank the solvents and compounds in order of increasing polarities.
Rank
1 (least polar)
2
3 (most polar)
Solvent
Compound
Fall 2009
A solvent that gives a high Rf value is said to have a high eluting ability. Rank the solvents in terms of
eluting ability for each of the three compounds.
Rank
Trans-stilbene
Vanillin
Vanillyl alcohol
1 (lowest)
2
3 (highest)
1. Do polar or non-polar solvents have greater eluting ability? Explain using observations above.
For each of the solvents used, rank the compounds (trans-stilbene, vanillin, vanillyl alcohol) in terms of
increasing elution rate (increasing Rf value).
Solvent
Compound with
lowest Rf
Compound with
intermediate Rf
Compound with
highest Rf
Hexane
Ethyl Acetate
Acetone
2. Does the order of elution vary according to solvent polarity? Explain using observations above.
3. Do polar or non-polar analytes travel faster on silica gel? Explain using observations above.