Hello all,

First time poster here basically at my wits end with this. We have a 10yr old Trace 1300 in our lab. We recently replaced the ECD about 2 weeks ago. For reference, the chromatography pictured is just hexane being injected prior to a sample being run. Things were looking great, chromatography looked awesome, but now all of a sudden I'm getting a negative signal and insane looking chromatography. Looking at the Hardware manual for the 1300, there's not really a mention of a negative signal, just mentions of negative peaks. There is a reference to high noise baselines, which is what the one picture is doing. I'm thinking about the following:

• Detector was installed 12/22/23 (currently 1/8/23) so very new
• Possibly considering heating ECD to Max operating temp per Thermo Maintenance guidelines to see if that moves the signal
• Possibly considering replacing anode (maybe we got a bad anode?)
• Possibly considering doing a complete re-install of the detector (maybe a bad connection/seating in the GC?)
• It's very unlikely, but possibly detector is faulty from factory? 
• Worst case scenario, and my boss & I have discussed, possibly internal electronics in the GC are just failing (or have failed) and we are going to need to get a new one.

I've been working with this GC for about 2 years now; so I'm certainly not an expert, but I'm also not green as grass. Anyone ever had this issue and if so, what did you do to remedy it?