Problems with the pressure

[Tequila]

Dear members of this forum,

I have problems with the solvents in the HPLC where I work. I am very strict with the variation of pressure when I am runing, the mobile phase is 100 % acetonitrile.
The variation of pressure is about 100 psi and tne average is 1000 psi. The technical service told me the variation is about to 40 psi not more. The acetonitrile is degased but I am convinced the problem is the degasification in line but I do not know.
I hope this problem happened in anybody of the forum. The model of HPLC is Waters 2690.
Thanks in advance for your help,

Diego

[Klaus I.]

If your suspicion is the degasser, you should try it without the degasser.

How looks the spurt out of the capillary to the column by a flow speed of 4 mL/min?[/quote]

[Koen Hollebekkers]

I guess that you have an air bubble in one of your check valves, or in the pump head. Try to purge the pump a couple times, otherwise ultrasonate the cheackvalves