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Size-exclusion and gas chromatography
cathy4208
#1 Posted : Wednesday, July 01, 2015 4:46:39 PM
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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
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Can you clarify where this question comes from?
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