This invention relates to the detection of molecular interactions between biological molecules. One embodiment of the extraction mixture includes a solution of bidentate organophosphorus extractant, dihexyl-N, N-diethylcarbamoyl phosphonate in a polar diluent, wherein bis-tetrafluoropropyl ether of diethylene glycol is used as the polar diluent at the following ratio of components: 0. The controller output signal operates such that a difference between an actual relation between the feed roll and cutter drum speeds and a nominal relation is at least reduced. The outlet includes an outlet connector extending outside the interior. The switching valve opens a communication passageway between the first air chamber and a second air chamber to connect the first and second air chambers when in the opened position, and closes the communication passageway between the first air chamber and the second air chamber to separate the first and second air chambers when in the closed position.