Science Buddies: "Ask an Expert"

I am doing a science fair project to see which type of sand separates the dyes in grape soda better than the other using column chromatography. In polarity red and blue are right next to each other. The dyes in grape soda are red 40 and blue 1.Would they come out in a close amount of time and how long would it take for the dyes to get out of the column without adding more soda?
In column chromatography silica or alumina gel is used. In my project would any thing replace the gel? Do you think different brands of sand with similar materials can also separate the dyes in grape soda?

Hello mallorywoodland,

There is a project on this site that seems to be similar to the one you’re working on:

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

Even if you’re not working on this project you may want to review the information provided.

The column material used in this project is a modified silica (Magic Sand). This material can separate the red and blue dyes in grape soda. My guess is that alumina gel would work as well as Magic Sand for this separation. I don’t think there would be any differences among different brands of sand (if all are unmodified SiO2). But I do think unmodified sand may perform differently than Magic Sand or alumina gel.

I think the amount of time the dyes would stay on the column would depend on the size of the column and type of column material.

I hope this helps. Please post again if you have more questions.

A. Norman