Chromatography Forum

Which ELSD detector is better: Sedere Sedex 75 or Alltech 2000ES

Thank you!

The quick answer would be the one that has been fully cleaned and tested. Both are older units and their condition should be highly suspect. Most ELSD (and CAD) detectors were abused (no professional cleaning or maintenance) by past owners then placed in storage for many years. Be cautious of third party equipment sellers who buy these broken units at auction and flip them for sale.

Perhaps a better question would be, why do you want one? They are best used by only the most experienced cinematographers, require a great deal of maintenance, large volumes of ultra-pure nitrogen gas (like an LC/MS system) and advanced curve fitting software for quantitative work. We have decades of experience using, servicing and training others in their operation, but in general do not recommend them for most applications.

Here is an article on HPLC evaporative detectors with more information that may interest you. "Evaporative HPLC Detectors; CAD (Charged Aerosol Detector) and ELSD (Evaporative Light-Scattering Detector)"; https://hplctips.blogspot.com/2017/12/e ... arged.html

from my personal experience Sedex is much more reliable. I am also not sure that there is support for Alltech detector because Alltech does not exist anymore and Vydac phased out almost everything (if not everything)

ELSD 3300, Buchi is the supplier now.

Thank you all for the help!
I end up ordering a used Alltech ELSD 3300. Buchi still sells parts. We will see how it goes - the compounds I have are very tough - natural polyamine like compounds. I use heptafluorobutyric acid for ion-pairing with RP chromatography.

You can do polyamines by UV with copper sulfate as visualizing agent. We have couple of methods for polyamines on our website. Coulple of our customers validated the method on Heritage MA mixed-mode column. Let me know if you have questions.