Abstract: The present invention provides a device and a method for automated liquid exchange in a horizontally rotating container that may be applied in automated sample treatment by using chemical solutions, in sequential order. Such applications include biomolecule staining on solid support or fixed samples such as western blot or tissue slice processing. Such sequential chemical reactions are usually performed on flat surfaces. Alternatively, these reactions can be completed with much less volume of reagents in horizontally rotating containers. Yet, it is difficult to automate these processes in rotating containers since the required tubing would twist due to the continuous rotation of the container. The present invention solves the problem of twisting of tubing by leading them through a stationary tubing carrier that passes through the rotating container.