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Unusual peaks and water dips in DI samples

Posted: Mon May 29, 2017 3:10 am
by lklee
Hi, my lab runs an Dionex ICS-1100 cation IC machine that usually shows a water dip at around 3 minutes, then 4 peaks (Ca, K, Mg, and Na) or none for DI samples. In the last couple of runs, though, the DI samples show a large spike in the first five minutes and then a large water dip at around 16 minutes along with an erratic conductivity behavior. We also found that the flow rate out of the column before the suppressor is about 16% lower than what it should be.
What we have ruled out so far is the DI water itself, and hopefully the columns since they were replaced only a couple of weeks ago.
Our next idea is the flush the system with a higher concentration of MSA acid but if anyone has any advice or experience with this kind of problem, we would be more than happy to try anything.
Best regards,
lklee

Re: Unusual peaks and water dips in DI samples

Posted: Fri Jun 02, 2017 6:50 pm
by JMoreno
How did you calculate flow rate out of the suppressor?

Was there any change to the system just prior to the change in behavior?

Is the chromatogram stable up until 16 minutes or is it erratic throughout?

Does pressure remain stable the entire time or is it erratic?