The invention relates to a container holder 10, comprising a main body 12 which in turn comprises a gas inlet 16; a solution liquid outlet 18; a gas control valve 20 through which a gas enters the container 100 from the gas inlet; and a sealing means 22 for the container, which sealing means includes a passageway 24 for the input of gas and output of a solution in the container via an egress tube 19; wherein when the container is connected to the container holder through the sealing means, the gas control valve opens automatically, and when the container is disconnected the gas control valve is closed automatically. The invention further relates to a container panel 50 which includes two or more container holders. Also disclosed are methods of using these containers and container panels for synthesizing a polypeptide.