Fluctuating pressure

[thohry]

Hi all,

I have this problem when running Hilic column: the pressure is about 94 bars, but the reading is rather fluctuating. I illustrate in the picture below.
Have anyone met this problem ?.
Thanks

[sassman]

That amount of pressure fluctuation could be normal for your LC system. Did it used to be smaller? With pressure fluctuations, I always try to clean the check valves first by sonicating in isopropanol. Sometimes a small particle can get in the valve and prevent it from seating properly. Bad seals can also cause pressure issues. But, like I said, this could be normal for your LC. We have a number of LCs that fluctuate up to 25psi or almost 2bar in normal operation.

[Consumer Products Guy]

I don't use that type of column, but at 94 bar, 2-3 bar fluctuations can be normal, 1 looks pretty good.