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- Posts: 26
- Joined: Tue Nov 26, 2019 10:39 am
im using an agilent 1260 series and im having issues with my quat valve/pump . i cannot get the same pressure profile.
i run 100 % (very low conc phosphate buffer) and then as soon as i introduce B (acteonitrile)its wavy. obviously the peaks are shifting as a result.
things ive tried:
-the quat valve has been removed and cleaned (multiple times)
-with a different quat valve i cleaned all the lines with 0.1 mol HNO3 and ran the gradient again with no columns and a restriction - ok
-with the different valve i ran the gradient with old columns - ok
-got back my quat valve, ran the gradient with brand new columns - bad
-the quat valve has been checked externally (with a gradient) and the pressure increases linearly across the entire gradient. (water/water with acetone)
-pump pressure fluctuations are <1%.
-completely purged lines at 5ml/min
-removed all lines and sonicated in 10% hno3. including frits
-replaced purge valve frit
-tried the same gradient with different channels (B/C and A/C) same wavy profile.
i have had issues with algae in the past. so i am going to clean my valve with HNO3 and repeat the same steps.
does anybody have any suggestions what to go to next because i am totally out of ideas.
below is pic of the pressure profiles of 3x injections one after each other. just MQ water and running gradient
if image doesnt work here is the link: https://imgur.com/a/fFSNOG0
Extra info: the valves are not leaking (switch off the quat pump module and all the valves automatically close - no leaking)