Greetings everyone!
I would like to determine the MW of chitooligosaccharide. I have already determined the Average-viscosity MW using viscometer.
I have done lot of search on size exclusion chromatography and many type of cloumn was used but I could not find the specific standard used for SEC. SEC has been done either HPLC with or multi-angle laser light scattering (SEC–MALLS).
Is it possible to determine MW with SEC just like we do for proteins. Please suggest me if there are other ways to do so.
Thanks in advance.
Yes. You can obtain MW standards that you can obtain from many manufacturers. An example is 'Dextran Blue' which has a MW of >1,000,000 daltons and elutes in the void volume. Insulin which has a MW ~50,000 daltons elutes much later. Each individual column has to be calibrated!
Thank you for your answer Bruce Neagle . What I can conclude that, I can use proteins standards (BSA etc.) for estimation of chitooligosaccharides.
Yes. But remember the elution profile can also be influenced by the shape of the molecule, electrostatic influences...
Martin Soucé Thank you for your insight comment. What MW standard do you suggest as I tried to find so but the MW is much lower than the my sample (determined from viscosity).
Dear Avatar,
Did you ever consider to use static light scattering for the determination of the molecular weight? I could really recommend the use of an SEC-MALLS approach over your suggested approach. For chitooligosaccharide you could even use an standard SLS instrument for the determination of Mw. As far as I understand you are only interested in an average Mw. With SEC-MALLS you could even assess the Mw distribution. If you need any information about light scattering theory, feel free to contact me or visit our light scattering theory page: https://zentriforce.com/company/zentriforce-academy/dynamic-light-scattering-static-light-scattering-theory/
beste regards,
Marius
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