[takeABow]

I am looking for a SAFE substance that is either:

Soluble in mineral oil but will extract into water.
-or-
Soluble in water but will extract into mineral oil.

Safe = Non-toxic, Non-Carcinogenic, Low Reactivity.
Ideally this substance should exhibit a color in one phase or the other.
This would be used as a student experiment for a Unit Operations Lab.  The old extraction experiment used a known carcinogen and was discontinued. 

Thanks in advance. 

[Grundalizer]

You're basically asking for something that is soluble in water and mineral oil, which is a fail.

Do the liquid CO2 extraction of d-limonene from orange peels.  Google it.

[nox]

http://edisk.fandm.edu/chm/VanArmanLab/Extraction/Extraction.html

Not exactly what you were asking for, but I think this would be perfect for what you want to demonstrate.

The chemical, N,N-Dimethyl-4-nitrosoaniline can be bought cheaply from Sigma ($43.40 for 25g)