Low Conductivity on Metrohm Compact 761

[aspencer]

I have an old Metrohm Compact 761 with MSM suppressor (no CO2 suppressor) that my lab acquired used. I've been spending sometime getting it up and running these past few months. I seemed to get past quite a few hurdles and things were running fairly smoothly. A few weeks ago when I started it up, my conductivity (which normally reads around 15) was reading less than 1. I checked the conductivity of the waste line with a handheld meter and got a reading of 15, so I knew it wasn't my eluent. I ran through a bunch of troubleshooting with Metrohm with no real resolution. I sent the detector off to their facility. At their facility they got conductivity readings around 15 and found nothing wrong with the detector. When I got the detector back and hooked it up it started working fine again. I ran some QC samples this morning looked fine, and then started my sample and the conductivity dropped again. Stopped the sample and just ran eluent and it is still low. Has anyone every experienced this? Metrohm now thinks it is a board, but when I run the troubleshooting test for the board it passes. These intermittent issues are so frustrating!!!

[Markus Laeubli, Metrohm]

Sorry for the late response.

What happens if you inject a standard solution while the reading is low?
Do you see the peaks?
If yes, how is the quantification?

What happens if you shut down the instrument and turn it on again?

Best regards
Markus