HPLC - Pressure climbing

[TheresaHague]

Hi,

I am using a RP-C18 column by phenomenex. The solvents I am using are 70% Methanol and 30% Water.
For some reason when I inject even the lowest concentration of a vitamin E like substance i.e. 1ppm of a vitamin E like substance in methanol the pressure continues to climb up to 3500.
Is there anything you can suggest to prevent it?

Many thanks

[Rafael Chust]

Dear Theresa:

Is the pressure climb momentaneous or continuous?

What is the particle size?

Are you using a guard column?

[oalamu]

In addtion to Rafael questions, at what flow rate are you running?And check if there is any leakage.