There is no one single reason which may cause high conductivity: wrong supressor or end of lifetime, failing power supply in electrochemical supression etc. I am a bit confused about the retention time shifts, which may point to (presumably high because of your problem) eluent concentration - too high for your supressor setup? Please can you tell me what is the unit of "2" and which ionic concentrations you expect, calibration ranges, which ions you need to determine etc.? BTW, what chromatographic system you use and did it ever work before?

Regards

Thomas

Dear Thomas,

Thanks for the help, I am using Dionex ICS 1100 system , i have a problem with cationic suppressor and  it is fixed to system that it should stabilise at less than 2μs/cm. I am determining Sodium, Pottasium, Calcium and Magnesium.

Thanking you,

Regards,

Praveen.

Dear Praveen,

I suppose you use MSA as eluent? (Sulfuric acid has been replaced by Dionex decades ago.)

Normally I start troubleshooting by checking each of the components, the sequence depends on the error. (Failing or unstable pressure require a differing approach, for example.) To make sure that the problem is the suppressor, I probably first would bypass column and suppressor by shortcutting pump and detector and pumping milli q water to bring the conductivity reading of your detector down to that of your milli q water. Drop of conductivity should be prompt, otherwise you might suspect contamination or dead volume, where the injection system would be a good guess to start fixing with.

Provided detector and injection work fine I would check once more the concentration of the eluent.  Something like 20 mM MSA is recommended for CSRS suppressors and IonPac CS columns for your cations. Further, supposed you work in the so-called "AutoSuppression recycle mode", the best indication of suppression is the appearance of gas bubbles in the outlet tube of the suppressor. Do you see these bubbles? Or do you use a different setup?

You also might compare the condictivity of your eluent (measured separately) with the detector reading, which - again provided the detector works fine - would give you some hint wheather you have weak or no suppression at all. Also I recommend to check power supply of the suppressor.

Best regards

Thomas