Dionex ICS-3000 baseline issue

[Jesterrose]

My baseline for my ICS-3000 looks like this.

Last time I ran conductivity, it looked fine (2 months ago). I have been running using an ECD and switched over Sunday.

I spoke to technical service and did all the typical troubleshooting steps
-replacing the detector
-New water source
-replacing the suppressor
-cleaning the cr-atc
-used both detector sides

(we also replaced the TEC board with a new one)

He would like us to schedule a service call, but has no idea what they might look at.....


We are running with a KOH gradient/cr-atc/as-11HC/supressor/crd-200/conductivity detector and are looking for different acids.

[John Guajardo]

Hi Jesterrose,

• If you acquire the pressure channel at the same time, do you see corresponding changes in the pressure baseline?
• What is your normal operating pressure and flow rate?
• Are you degassing your DI water before putting it on the IC system?
• Have you primed the pump thoroughly, at least 5 minutes for each channel (100% A, then 100% B, etc.)?
• How many backpressure coils do you have installed between the conductivity detector cell outlet and the suppressor regen in?
• How does the baseline look if you run your DI water from the pump outlet directly into the conductivity cell inlet (bypassing all consumables) at 1 mL/min? You may need to temporarily install a piece of yellow backpressure tubing between the pump outlet and detector cell inlet to ensure the pressure stays above 200 psi during this test.

[Jesterrose]

The pressure is stable. Running isocratic with degasser water. I did prime it thoroughly (set it to rin 30 min) but will sonnicate longer.

My pressure is right at 2500 psi at 1 ml/min.

It is in external Regen mode so I have no back pressure coils installed as the detector goes to waste.

I will buy pass the system again with this new detector and see what it looks like.

[John Guajardo]

Thanks for that info. I would also recommend installing one backpressure coil (p/n 045877) at the detector outlet and see if things improve. See section 2.4 and 3.4 of the suppressor operators manual for more info:

http://www.dionex.com/en-us/webdocs/114493-Man-ERS-500-Suppressor-031956-09.pdf

[ljc]

You said you're using an ECD but it's actually a CD right? Are you using an EG? If so maybe the EG degasser is bad. The 3000 has a separate degasser in the module. It appears that you get more noise spikes at higher KOH on the baseline, which is where there is more gas generated.