UPLC reliability issues

[seamoro]

Ive had reliability issues with our waters UPLC for some time now. I have posted multiple times about building pressure issues and the only way i solve it is by taking the head off the column and replacing the 0.2um filter. Thta works for a while until i need to do it again. Waters have blamed just about everybody and everything...filters...technique...solvents and bascially i believe i have eliminated all of these. I have no idea what cause this problem!!...any ideas...cause im totally out of them!

[Peter Apps]

What makes you believe that you have eliminated all possible sources of whatever is clogging the filter ?

Peter

[MSCHemist]

When I was running my Agilent 1290 to avoid building pressure I'd
1. Not use pure water on any channel. I used 10% CH3CN on channel A
2. I always ended a run with a cleaning that left the column in 100% CH3CN
3. I used an inline filter. the smallest available for Agilent was 0.3um
4. I used a bizarre but effective cleaning procedure where I alternated between A water with 0.1% TFA acid and B 33% IPA/66%CH3CN/0.1%TFA. I ran a 30min gradient from 20% to 100%B at 80deg (max column tolerance) 3 times with max volume injections of trifluouroethanol. I did a lot of experimentation with cleaning columns and this one was a miracle. I even tried running heptanes at low flow overnight to clean the column and that usually didn't do much (I ran reverse phase)