You probably can, at least with the better generators. I know that you can make colloidal copper with Utopia Silver's Silver Bullet Colloidal Generator (described in another post in this forum) by purchasing copper anodes. I believe you can also make colloidal gold - but only if you use a high voltage system.
Yes, it is indeed possible to make it by that method. There are other techniques as well, but they do reuire one to have serious lab equipment (and, of course, some amount of aptitude in chemistry .
Please try to learn as much as possible about the subject before jumping into it! Find more info at colloidalcopper.net