Chromatography Forum

My problem has begun 30 days ago. When I turn on my HPLC I observe to low pressure and large pressure fluctuations. My pressure should be 9 MPa, but when I turn on HPLC, pressure is only 4 or 5 MPa and it fluctuate about 20-30%. Of course I start to purge the pump, but it takes me 1 or sometimes 2 hours. When venting is finally finished pressure is very stable, fluctuate less than 2% and pressure is 9 MPa. Earlier I didn’t have such problems, purging was necessary only after, for example, 10 day long brake in apparatus usage
I have on line solvent degasser.
Please help me resolve my problem.

The degasser needs mending.

Better yet: Toss it away and degass your mobile phase prior to use.

Best Reards

Thank you for your answer. But I have doubt.
If degasser is damaged, why after long pump purging pressure back to normal?

Well, then we’ll have to remove your doubts
In the beginning the air bubbles released in the pump heads and elsewhere in the system are very tiny. Over time they “find friendsâ€