noisy baseline HPLC ECD

[yonit]

Hello
I'm working on HPLC ECD of ESA.
The HPLC was shut down for a couple of months and then was switched on, the system washed and column was applied. I let the system to stabilize over night. The baseline was unstable and noisy. The response was low then the usual. The technician told me (over the phone) that the cell was damaged. We tried to wash it with solvents as written in the cell's guide with no improvement. So we changed the cell and the same unstable noisy baseline was observed.
I read that noisy baseline can cause due to:
1. Air bubble in the pump so I purge the system.
2. Air bubble in the cell - 100% EtOH can remove it so I washed the cell with EtOH.
3. Leak - there is no leak.
I find it very strange that both cells damaged at the same time...
Is there any other module in the system (detector, pump...) that can cause such problem?
If anyone has suggestions I'll appreciate it.
Thank You
Yonit

[aceto_81]

I have only experience with a cell from Antec, but here we go:
We sometimes experience some brown substance in the cell. After cleaning with 2 M HCl, this is dissolved and baseline is back to normal.

Other thing we already got: an inline filter of the HPLC was clogged and gave some issues because of the pressure variations introduced.

Good luck

Ace

[yonit]

Hi
Thanks for the reply.
When the problem started I changed the filter that come before the cell - didn't help the baseline stability
I washed the cell with MeOH, ACN, THF, ACN, MeOH, H2O - as per the detector guide for maintenance of the cell performance - didn't help
Other suggestions?

[aceto_81]

Hi,

maybe passivate your system?

Ace