If a compound interacts strongly with the stationary phase, it will elute:

If a compound interacts strongly with the stationary phase, it will elute:

• A. Quickly
• B. Not at all
• C. Slowly
• D. Immediately vanish

Answer: (C)

In chromatography, how long a compound stays in the column depends on how strongly it likes the stationary phase. When a compound binds strongly to the stationary phase, it is retained longer as the mobile phase moves through the column. That extra sticking time means it takes longer to travel from the top to the bottom of the column, so it exits the column more slowly. So the correct idea is that a strongly interacting compound elutes slowly. If the interaction were weak, it would be carried along by the mobile phase more quickly and elute sooner. Saying it never elutes isn’t realistic under normal conditions, since the mobile phase will eventually pull even strongly retained compounds through, just at a much slower rate.

In chromatography, how long a compound stays in the column depends on how strongly it likes the stationary phase. When a compound binds strongly to the stationary phase, it is retained longer as the mobile phase moves through the column. That extra sticking time means it takes longer to travel from the top to the bottom of the column, so it exits the column more slowly. So the correct idea is that a strongly interacting compound elutes slowly.

If the interaction were weak, it would be carried along by the mobile phase more quickly and elute sooner. Saying it never elutes isn’t realistic under normal conditions, since the mobile phase will eventually pull even strongly retained compounds through, just at a much slower rate.