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Polyamide oligomers by FFF - MALS

Posted: Mon Nov 25, 2019 7:49 pm
by Gambit88
Does anyone have any experience in analysis short (up to 5000 Da) linear oligomers of polyamide by FFF - MALS? Currently my equipment (in aqueous mode) allows me run analysis with eluents only up to 20% of methanol. Is it even worth to try analyse this oligomers in such a mode?

Re: Polyamide oligomers by FFF - MALS

Posted: Sun Jan 31, 2021 4:47 pm
by DanSome
Hi,

While it is possible, FFF-MALS is not really a good solution for such small polymers, up to 5000 Da. Current FFF-MALS instrumentation from Wyatt Technology can certainly handle higher concentrations of methanol, and you can use regenerated cellulose ultrafiltration membranes though you might have to cut out your own membranes due to the low MWCO required (the lowest standard size is 5 kDa but you would need 1 kDa or less, depending on the lowest size present).

I recommend SEC-MALS for this analysis. Then you will not have to deal with finding low MWCO membranes or any solvent limitations.

best,
Dan