Chromatography Forum

I am using a 5µ RP C18 column 4.6 mm x 150 mm on a standard 1100 machine.

The EP method that I am trying to run asks for a flow rate of 1.5 ml/min with 93 % Water, rest AN. Column @ 40°C.

At this rate I am getting a pumping pressure of 180 bar. I am concerned if this is good for the machine or the column in the long run.

I don't want to deviate from the prescribed method and lower pumping rate and at the same time feel concerned. Did any one have a similar experience.

Hello

1. Depends on Agilent pump (Binary or Quat) you can run up to 600/400 bar
2. Check pressure limit in column datasheet (reference guide)
3. In general if RP column has no "aquaproof" parameters it is not good idea to run mobile phase with 93% water

Regards

Tomasz Kubowicz

It's not a problem. There are very few C18 columns rated to less than 400 bar, and an 1100 is rated to 400 bar, so it's well within the working specifications. I personally wouldn't worry about 7% organic either - have never had any hint of phase collapse working even lower than that on Phenomenex Luna and Kinetex C18 columns.

I agree with Imh. Some years ago one of my customers for the first XTerra C18 columns run his 1100 system day by day at 340bar.
Both column and system were fine. Average 500 injections and no increased intervals for maintenance of the instrument. Customer was happy.
Good luck and don't worry.

Fine. Why did you think that pressure was "too high"?

Many Thanks for the responses. So I suppose all is well.