Science Buddies: "Ask an Expert"

My daughter is working on the project "Column Chromatography: Can you Separate the Dyes in Grape Soda Using Space Sand™?" She did this experiment last night. When she did, the eluate became slightly clearer with each fraction and the sand basically did not change color. She followed the all the directions, but still wondered if she might have done something wrong. The dyes really did not separate and that was not the results we were expecting. Did we mess up? Any ideas of where we went wrong?

Hi Mom,

I think your daughter is doing this excellent project from this website:

https://www.sciencebuddies.org/science- ... p045.shtml

The separation of the red and blue dyes in the grape soda depends on a polar interaction between the dyes and the sand. If your daughter has trouble seeing the dyes on the sand, then it’s possible that she needs to use more soda to make the sample visible. Or, if the sand had some color to it, it could mask the dye colors. Did you daughter use perfectly white sand?

If there was no separation between the two dyes, then try using a longer or thinner column so the sample has more time to interact with the sand as it travels through the column.

Please do try again and let us know what happens.

Donna Hardy