By Andrew Scott on Thursday, July 29, 2004 - 08:35 pm:

Hi everyone

I have a problem. I don't have very much GPC
experience at all but have a question that I hope might
be able to be aswered.

I want to quantify molecular weight distributions of a
polymer blend by GPC. I am not aware of software that
may enable this process to be performed. Is there any?
I hope to purchase a Waters Breeze system soon. Does
anyone have any good/bad experience with this system
for running GPC? The only thing I can think is to run
several columns in series and hope for base-line
resolution.

Thanks in advance

Andrew

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By A on Friday, July 30, 2004 - 10:29 am:

There are numerous softwares (often attached to systems) available which can do this calculation, Breeze software (and system) is among them. I have used that system for this and it worked well enough.

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By PETER on Monday, August 2, 2004 - 08:15 am:

There are many vendors of SEC software.Their software allows you to determine molmass averages.
You want to quantitate one polymer in a blend,
that's a different question, and the problems you will have are the same like with low molecular substances: you need separation (the better - the more reliable the results).
Unfortunately SEC creates only low resolution,esp.
if your polymer coils are of the same size.
Several columns in series improve the separation
but mostly it is not enough.
One possibility might be by injecting the overlapping polymer and e.g. pushing up that file by electronical multiplication(get the multiplic.
factor in the overlay mode by trial and error until that file coincides with your sample run).Now you can 'clean' the overlapped polymer in the sample run by file subtraction.If your instrumental conditions had been excellent (baseline drift,noise...) you might get a new file with a standalone polymer for further quantification.
Another way could be via extra peakfitting software.
I would prefer the chromatographic approach, i.e. change the mode.
Gradient elution techniques are very powerful for the separation of blends based not on polymer size but on properties like different solubilities
or different hydrophobicities of the components.