Aside from the immiscibity with water, MTBE does have some common features with THF as a chromatography solvent, but is more popular as a normal phase solvent, esepcially for lipids, and vitamins.
Initially, the impurities in available grades compromised the use in nromal phase, but HPLC grades are much more pure these days. It's OK, but you have to watch out if you use it with hexane, because the low viscosity of blends can give problems with some pump check valves and seals.
The comment about not forming peroxides as easily as THF is correct, but MTBE is more often used as a replacement for diethyl ether, which also forms peroxides easily, and is also fairly water-immiscible.
MTBE also is only about a third of the price of THF, and has a slightly better UV cutoff. II can remember when we paid US$100/litre for the first HPLC grade of MTBE available locally, but it faciliatated a separation we hadn't been able to achieve, so it was cheap....
I think your colleague may have mis-remembered a little, but is not a complete idiot. Additionaly, I prefer the smell of MTBE over THF. The Use of MTBE should be covered in most standard texts ( Snyder, Kirkland, Glajch ) and I think it was discussed in Sadek's book as well.
Bruce Hamilton
