Chromatography Forum

It is an Agilent 1100 system with a quaternary pump. It makes sound when it is working. Is it because it is dirty?

By the way, shall I keep the pump running all the time, or shall I turn off the pump over night.
If I turn the pump off, I am afraid it is going to run dry in the system. If I leave it on, it is working all the time, and the lifetime of my pump would be shorter.

thanks

I wouldn't worry about the sound, some of our Agilent quat pumps simply make more noise than others. We turn most of our pumps off at the end of the sequence, except when using non-volatile buffers or when keeping in "ready" state. If you want to keep the pump running and not go dry, just run a low flow rate like 0.05 ml/min (use lower pressure limit setting). If the pump runs dry, then you'll have wear....

I'm curious if you're running Acetonitrile in your mobile phase? We've noticed with some pumps, the acetonitrile seems to cause a squeaking noise.

I'd recommend turning your pump off when not being used because the seals will wear faster if they are in constant use. If the system is properly primed, once you turn the pump off, your system won't just drain itself dry, the mobile phase will remain in the system for a while. Long-term storage would be different. If you use your system on a regular basis, whenever you turn your pump on, you should prime it anyway.

Thanks for your replies.

rnelson, yes, I have acetonitrile in my mobile phase.