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Sedex 75 ELS Detector

Posted: Tue Jun 23, 2009 5:46 pm
by John R. Carver
Will 0.10% H3PO4 or 0.10% H2SO4 harm a Sedex 75 ELS detector?
I will be using a Supelcogel H column with ~ 0.50 ml/min.

Posted: Tue Jun 23, 2009 6:44 pm
by Vlad Orlovsky
You cannot use these acids with ELSD, you will have huge background. Try TFA instead (as strong acid).

Posted: Wed Jun 24, 2009 1:07 am
by Kostas Petritis
Agree with Oleg, and I hope that you understand that the problem is not the acidity of the additives but their non-volatility...

Posted: Wed Jun 24, 2009 1:54 am
by Vlad Orlovsky
Kostas....who is Oleg??? LOL

Sedex 75

Posted: Wed Jun 24, 2009 7:57 pm
by Ticoscen
The 75 can tolerate low concentrations of buffer in some cases depending
on the percentage and gain settings. Turbidity of any kind is detectible,
no matter what it is. Silica bleed, stale dihydrogen oxide (water)
and residues after evaporization (old chlorophorm).
These will all generally increase stray light levels and add noise.

The 75 itself has an all stainless steel tube for the majority of the
length of the heater / evaporization tube which is pretty tolerant and robust. The older 55's had nickle plated copper tubes that
were much more prone to the generation of copper and nickle salts
from chronic use of acids or corrosive buffers.

TPR

Posted: Wed Jun 24, 2009 11:16 pm
by Kostas Petritis
Oups! Sorry Vlad! :?

:D