Page 1 of 1
sedex 75
Posted: Tue Sep 10, 2013 7:14 pm
by sepscientologist
I am using a Sedex 75 with chemstation via the 35900 data acquisition box and having a strange problem. I can see the top
of the peak but at a particular threshold the signal just goes to zero. The top of the peak looks fine though. Anybody have any ideas?
Re: sedex 75
Posted: Wed Sep 11, 2013 6:08 am
by Gerhard Kratz
At what wavelength you are messuring? It Looks like there is more than one compound under your Peak.
Re: sedex 75
Posted: Wed Sep 11, 2013 2:43 pm
by tom jupille
It's an ELSD; wavelength is not involved.
The bit of signal before and after the shift look remarkably flat. Is it possible that the baseline offset is such that the data system/display is seeing a negative voltage in that region?
Re: sedex 75
Posted: Wed Sep 11, 2013 9:56 pm
by sepscientologist
That's a good suggestion Tom. I know the 35900 doesn't handle negative voltage.
I turned the thing on and was going to measure the analog output but everything
was working perfectly. I should have turned it on/off before. Amazing how often
that will fix things!