I'm currently writing a paper in a class about writing papers (go figure) and I'm stuck on whether or not I can cite something in the introduction. I can't find anything concrete on whether or not it was allowed.
The MLA Handbook (8th ed.) does not mention the use of citations within introductory text at all.
Barring their proscription, I can only assume that the rules for such in introductions are the same as for anywhere else in the body of a piece of text.
Unless a publisher says not to do it because of their own house style, I see no reason why you shouldn't.