Chromatography Forum

After about a month the 2nd channel starts to lose sensitivity and resolution, so I change the column, which I just did last week. I ran once and the peaks were shaped beautifully, but when I tried a second run the 2nd channel went bad again. I ran a bunch of rinses thinking there might have been some debris, and then ran a low level standard. It had gotten worse. When I take the cover off the top of the detector it looks like there is a copper sleeve on the first detector that isn't on the second one, and the post coming out of the top of the second one is loose. Anyone have any ideas?


Sorry about the huge photos. No photo editing program at work.

JReed,

The second one appears to be missing the insulator that isolates the collector anode from the body. Therefore, you can either be leaking through this fitting causing noise or you can be wiggling and grounding through this fitting (causing noise.)

Best regards,

AICMM