Described embodiments provide devices, systems and methods for sequencing liquid flow in response to a driving force by entrapping and releasing gas between volumes of liquid in a controlled manner. In one particular form, a centrifugal “lab on a disk” device is provided to drive liquid flow and sequencing by virtue of the centrifugal force and in one particular form a radially inward bend conduit is used in connection with controllably trapping and releasing gas between liquid volumes.