A device for evaporation treatment of sample material in a container, said device having a microwave-operated heating appliance, a heating chamber and a holder for at least one container in the heating chamber, the container being connected to a line, characterized in that the line has in the peripheral region of the container a releasable line connection which is established by insertion movement on insertion of the container into the holder and is severed by removal movement on removal of the container from the holder as a result of relative displacement of portions of the line connection.