soybean based... my first thought is a massive lol, my second though is that it must be really well purified... i think you could probably dissolve a wide variety of polar dyes in it, but i cant name any off the top of my head (im no dye expert), just make sure it doesnt conduct electricity
yeah fluorinert can get really expensive if you want any decent amount, but it will dissolve just about any dye you could stick in it, so finding a suitable one would be no problem... but the expense really outweighs this perk
either way, i think their answer was more a "figure it out yourself! what do you think we're paying you for?!?!" kinda answer than anything else lol!