Welcome Guest Search | Active Topics |

Tag as favorite
Size-exclusion and gas chromatography
cathy4208
#1 Posted : Wednesday, July 01, 2015 4:46:39 PM
Rank: Newbie

Groups: Registered
Joined: 6/29/2015
Posts: 8

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
I was wondering if someone can clear up this question:

If size exclusion chromatography (SEC) were used to separate a mixture of ethylene glycol oligomers, as shown below, with fractions further purified by gas chromatography (GC), what might be expected?



A) The use of nonpolar solvents in SEC will lead to good separation and efficient purification by GC.

B) The use of ether-type solvents in SEC will lead to poor separation, and subsequently to inefficient purification by GC.

C) Oligomers with long retention times on the SEC column have long GC retention times.

D) Oligomers with short retention times on the SEC column will have long GC retention times.

From my understanding, size-exclusion chromatography elutes large compounds first because they can't go through beads easily. So, large compounds then should have short retention times on SEC. If they're large, then they are less volatile, so they would have longer GC retention times. I'm not sure where my understanding is flawed; I would appreciate any clarification.

Thanks!
alfredbasilious
#2 Posted : Monday, July 13, 2015 4:40:43 PM
Rank: Instructor

Groups: Registered
Joined: 5/25/2012
Posts: 5

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
Can you clarify where this question comes from?
Users browsing this topic
Guest
Tag as favorite
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Clean Slate theme by Jaben Cargman (Tiny Gecko)
Powered by YAF | YAF © 2003-2009, Yet Another Forum.NET
This page was generated in 0.095 seconds.