Chromatography Forum

Hello, I'm new to the forum. I have a HP 5890 II with ECD and a HP 608 column. The point is that when I set the oven temp above 220ºC the baseline shows very low noise. If I set the oven temp 140ºC automatically the baseline increases significantly the noise level...

Any suggestion or comment? May be the column is the problem?(the column is not new)

I appreciatte a lot your help. Regards from Argentina. Raul

I'm not familiar with the 608-type phase, as I've never used it. But, perhaps uninstalling and reinstalling the column would be of benefit here. There could be leaks form the old ferrules if they were reused in this current installation. Changing the ferrules would be key, here.

Also, has you gas/gases been changed recently? Is your anode purge on (I think ours are at 2-5mL/min)? Is the makeup on (about 30 mL/min if I recall correctly)?

If that doesn't do the trick, maybe you've been inside of the ECD before? That's a last resort to open up the anode gas supply at the ECD to check the liner.

Hi

I agrre that the ferrule is the most likely issue here, the problem seems very familiar.

I assume you use a 85/15 vespel/graphite ferrule (for temperature gradients) and not a 100% vespel ferrule (for isothermal) at the detector side?

You tend to have to retighten vespel ferrules now and then.