Abstract: Substantially sealed microfluidic devices for performing pipettorless ratiometric dilution are provided. In one embodiment, valves are disposed between and permit selective fluid communication between multiple chambers of a series of chambers. In another embodiment, a mixing chamber receives fluid from an inlet port and is in donative fluid communication with multiple receiving chambers each having a small volume than the mixing chamber. Active mixing means may be provided, including moveable magnetic elements, sonication, and mixing channels coupled with fluid transport means. A material transport system may be used with a non-electrokinetic pipettorless dilution system for transporting sample, diluent, and combinations thereof within the device.