Thread: Extract food dye from Froot Loops?

Hey all,
I have to do a lab write up on the "Determination of the Mass Percent of a Dye in Froot Loops Using a Spectronic 20".

Most of it I can figure out by I'm stuck on how to extract dye from the froot loops.

My only idea is that maybe I can let it dissolve in a known amount of water and then measure absorption and use Beer's law to come up with the concentration and go from there. That doesn't seem like a very elegant way to do it though... Any other ideas?

First of all, you have to know what the dyes are. They are yellow 6, red 40, blue 1 and blue 2. The are all sulfonic acid derivatives:
Yellow 6

Red 40

Blue 2

Blue 1

There are many other compounds in froot loops that are water soluble so this would not be a good way to isolate. If you have just a ton of time in the lab and an endless supply of organic solvents, I would try some organic solvent extractions just to see what happens. Come to think of it, I didn't realize this was an exercise in spectrophotometry, so in theory the only things in froot loops that will absorb visible light are the dyes. That being said, I might try the water idea. From this you should be able to get the mol/L then using the molar mass you get mass percent for each dye based on the absorption for each relevant color. Good luck separating blue 2 from blue 1. I would still try the organic solvents afterwards just for fun. Start with DMSO because DMSO is kewl.

I found the same lab online here:

http://chemistry.bd.psu.edu/jircitano/beerslaw07.pdf