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IC : uneven baseline using Dionex 5000 RFIC system

Posted: Mon Apr 08, 2019 5:25 pm
by Kuju
Hello,
I ran a seven anion standard mix and the baseline of my chromatogram is not all even. For each of the 7 individual peaks in the standard, each peak would start to rise at 0 uS but as each peak goes back down, the peaks will drop a bit lower than 0 uS and then would slightly go back up again to 0 right before the next peak would come out. Therefore, between each peak there would be an uneven baseline. Also, when I ran this standard about a month ago, I was getting a stronger signal for each of the anion peaks. Would anyone have a suggestion on what I could try to fix this or how I could narrow down what the issue might be? I have a Dionex 5000+ RFIC system, that has a suppressor, a continuously regenerated anion trap, and an added carbonate reducer. I am also currently doing auto-injections.
Thanks for any suggestions.

Re: IC : uneven baseline using Dionex 5000 RFIC system

Posted: Tue Apr 09, 2019 9:03 pm
by John Guajardo
Hi Kuju,

Welcome to the forum. Based on what you have described- negative dips immediately after all analyte peaks and overall reduced response- it sounds like your suppressor capacity may be slightly depleted. Please try the chemical regeneration described in section 5.2.1 (steps A-C on page 77) of the suppressor manual (link here).