Question

A student loaded a mixture of compounds for column chromatographic separation in 1 mL of ethyl...

A student loaded a mixture of compounds for column chromatographic separation in 1 mL of ethyl acetate, then proceeded to elute with pet. ether/ethyl acetate 10:4. She found that all of the mixture came off in the first 4 fractions, with no separation. What technical mistake did the student make?

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Answer #1

The Polarity of the compounds is not given. If it is we can answer still accurately

Mobile phase (Solvents) , Ratio of the mobile phase, Stationary phase (Length of the column), will impact on separation of spots.

Mistakes

1. It might be non polar compounds. She should have eluted in minimum ratio of ethyl acetate

2. Packed column length might be very less which will not allow the separtion between the spots.

3. Or she might have changed the solvents. she may have used ethyl acetate /ether in 10 : 4 ratio instead of ether/ethyl acetate

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