HPLC Columns with different Endcappings
Posted: Sat Dec 02, 2017 10:03 am
by Fawad
Hi,
I would like to have expert opinion on the following.
1. in HPLC, which endcapping you prefer, Gas phase or liquid phase?
2. HPLC columns with polymeric bonding or monomeric bonding?
Re: HPLC Columns with different Endcappings
Posted: Mon Dec 04, 2017 11:43 pm
by tom jupille
The short answer is "whatever works".
The somewhat longer answers:
1. As far as I know, manufacturers/vendors rarely share the details of how bonding or end-capping were carried out.
2. "polymeric bonded" columns (often referred to as "high carbon-load) are actually relatively uncommon now. When I started doing LC 40 years ago, the silica used was horribly impure by today's standards, resulting in a high level of "active" silanols which gave rise to major tailing problems. Using a thick polymeric bonded phase masked the problem to a certain extent but arguably hurt efficiency because of slow diffusion in that bonded phase layer. Columns developed over the past decade or so start off with high-purity silica and exhibit much less tailing even with "monomeric" bonded phases.