For a number of reasons, this is not a good idea. E-Cig does sell "health" liquids, one with C. The question is how much of the vitamin do you get in the vapor. Probably not much.
And for do-it-yourself: do not add any oil-based vitamin product; you don't want the powdered form either.
I have both the normal crystalized Vitamin C that I stir into orange
juice, and a special fat-soluble C to use in gravies. I have Vitamin E in gel, liquid and powder form. But these are best taken with food that will be digested. There's no need to inhale them.
Please abandon this idea and get your vitamins in or with food.