I was experiancing high backgroung signal on my ecds after a gas change. Assuming it was the N2 i changed to a new tank and the signal droped only slightly, (3200Hz to 26000Hz). The original signal was at around 600-700Hz. I tried baking both the ecds and columns.I went as far as to cnge columns to see if that was the source of the problem. Nothing has worked. The signal is not droping and there are signifigent baseline shifts and negative peaks all throughout the run.
By chromatographer1 on Tuesday, August 10, 2004 - 06:00 am:
bad gas. change the cylinder for goodness sake!
By GC user on Tuesday, August 10, 2004 - 12:11 pm:
All the lines going to the GC and the internal tubing of the GC may be contaminated with whatever was in the bad gas. Flush out the nitrogen line with solvent and blow enough gas through to dry, replace the traps on the nitrogen line (at least I hope you have traps), and run a high flow through the GC lines.
Before doing the above, verify that the nitrogen line doesn't have any leaks, as air leaking in will also lead to a high background.