GC analysis of solvent in low MW polymer

Chromatography Forum: GC Archives: GC analysis of solvent in low MW polymer
Top of pagePrevious messageNext messageBottom of pageLink to this message  By J. May on Thursday, December 14, 2000 - 05:53 am:

What are the dangers of injecting a solution of a low MW polymer to determine the percentage of residual processing solvent on a capillary column?
The polymer melts at about 90 degrees, and vaporizes at approx 280 degrees. It seems to work, but I would appreciate anyones input. Also, I don't have headspace or p & t.....


Top of pagePrevious messageNext messageBottom of pageLink to this message  By H. Jamieson on Saturday, December 16, 2000 - 11:47 am:

The dangers seem obvious if the column is not capable of sustaining temperatures above 280C. The polymer will build up on the column, moving slowly to cover more and more of the stationary phase. I think the question should be, "How do I prevent problems from the polymer?". I have a couple of suggestions which may or may not help your particular situation.
[1]Run the solution through a SPE cartridge that will retain the polymer but allow the solvent to pass through.
[2]Use a packed or baffled flash injector or SPI run at a temperature high enough to boil off the analytes but cold enough to hold the polymer. Change the injector sleeve frequently.
[3]Use a long guard column. Keep the final temperature low enough to keep the polymer in the guard and replace the guard regulaurly.
[4]Back flush or wash the column on a regular basis if there is a solvent suitable to dissolve the polymer without harming the column. Varian has an excellent washing system for use outside of the GC.
[5]Reverse the column and have it hold overnight or over weekends at the highest possible temperature that will not damage the column. Under the conditions of your test anything that takes a particular time to move down the column should under similar conditions take just as long to be removed by reverse flow. It should be possible to remove them in less time at high temperature with a reverse flow.


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