Chromatography Forum

Hello everybody, I wanted to ask something about an HPLC LKB, the pump is a 2150 model. Recently I accidentally flushed the system with acetonitrile, and before that I was running a mobile phase with phosphoric acid 0.2%:acetonitrile (9:2). Anybody has an idea about how to clean the valves? I did it with some new equipments but I wanted to know if anybody had such a problem with an equipment that old.
Thank you very much in advance.

Generally speaking, remove the check valves and sonicate in methanol.

For phosphate I would use a mixture of methanol and water.
I am not sure about the model but our LKB pumps at Uni you could dissasemble the check valves, If you do that do not take your eyes of the ball. The ruby ball seals are extremely difficult to find once it drops on the floor, trust me.