Science Buddies: "Ask an Expert"

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I am doing this experiment but I need help on the the method. Im using orange soda in addition to grape soda and having a hard time separating dyes red 40 and yellow 6 from it. Grape soda works just fine but orange fails to separate and the dyes come out of the column all at once, looking orange.
Plz help and thank u

Hello gameon1510,

The sand column separation depends on a polarity difference between the dyes in the mixture. Possibly the polarity of the red and yellow dyes is too close for effective separation for your column configuration. You may be able to get a good separation if you make your sand column longer than the one you used for the grape soda. My suggestion is to try a column twice as long.

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

A. Norman

Thank you so much. I also recently discovered that same fact, and now i know for sure. Thanks again