Column Chromatography What affect would adding the crude product to the column b
ID: 1016036 • Letter: C
Question
Column Chromatography
What affect would adding the crude product to the column before the solvent was drained to the top of the alumina have on the chromatographic purification of fluorenone ?
A chromatography column, in progress, was allowed to sit over an extended period of time. What effect would this have on the separation of a product from its impurities?
Predict the order of elution of the following compounds from a silica gel column. Identify which compound would elute off the column first, second and third.
I picked Benzophenone, benzoic acid, and nitrobenzoic acid
Least polar to most polar...Is this correct?
Explanation / Answer
1. SOLVENT is mobile phase, if we allow the solvent level to go below the stationary phase, (known as letting the column to “run dry,”), it allows air bubbles and channel formation to occur leading to a poor separation and uneven bands formation.
2. Retention time (the ratio of the amount of time a solute spends in the stationary and mobile phases) changes.
3. the more polar the solvent, the faster compounds elute, regardless of the compounds polarity.