burcakk14301493,
Unfortunately I do not know of a Target native way to do this out of the box. However if I were tasked to accomplish this here is one way I would go about it at a high level:
1. Implementing some custom code that starts a timer on the page and fires a special mbox parameter if the required time is reached.
2. Build an audience in Target based on that specific mbox parameter.
Hope this helps!
Mihnea Docea | Technical Support Rep, Customer Care | Customer & Employee Experience | Adobe | (:: 1 (800) 497-0335