IC Baseline Drift/Lift Off

[zverduzco]

Hi,

Newer to IC and currently have an issue with my baseline.

My run is 27minutes and around 7-15minutes I get slight increasing baseline then at 15-22minutes I get a drastic lift in baseline. After 22 it comes back down to normal. I has been getting worse and worse as samples go though.

These times coincide to my EGC KOH gradient increase.
-at minute 8 the KOH begins to go up from 5 to 9mM, here i see a slight increase in baseline
-at minute 15 the KOH begins to go up from 9 to 20mM, here i see a drastic increase in baseline

This makes me believe something is wrong with our KOH EGC but we have been using this EGC for awhile now and not had issues prior and it still has ~45% life. We do not use a temperature control. The lab I'm in does not elevate in temperature either. I changed the column and suppressor (neither helped). Would changing the CR-TC help? Is there anything I can run through the IC that could clean it up or if anyone has suggestions I would greatly appreciate it!

[anionman]

That's normal when you run a gradient. I run a shallow one from 23 mM to 34 mM and it is only visible in blanks with very low anion concentrations.



the above gradient is Eluent: KOH gradient: 1 to 35 mM KOH from 0 to 20 min; 35 mM from 20 to 25 min; 35 to 1 mM from 25 to 25.1 min; 1 mM from 25.1 to 30 min
https://www.sigmaaldrich.com/US/en/tech ... pure-water