We are using GPC to determine MW of polymer. we are using multidetector analysis however we are getting Mw, Mn and other values o=for polymer 1000 times more than that of actual molecular weight. what might be the probable reasons for the same...???? Also our polymer is 95 % pure...??? Is this the reason for such a vast difference in molecular weight...????
Dear Vishakha Tambe, I think the solvent is not the appropiate one, may be the range of concentration is not adequate, and finally may be the chain are not linear and even with possible crosslinks. My Regards
Its an aqueous polymer we have used 0.02 % sodium azide as mobile phase. Concentration used is 1 mg/ml. We have got good response in RI, Viscosity and light scattering detector. Chains are not linear so that could be the reason for such increase in the different molecular weight values determined by GPC.
What is the stationnary phase ? Are you following a given reference in using sodium azide?
We are using PL aquagel-OH MIXED-H column from agilent as a stationary phase.It is specified for MW between 6,000 to 10,000,000.
Dear Vishakha Tambe ,
it is depend on the solvent and the polymer standard that you used for the analysis.
You indicate that your sample was at 1000 times 50kDa and that would be outside the specification limit of the column. If you see a nicely resolved distribution then there may be a calibration or input parameter error. If however this is just a single peak in the void volume, the method may not be appropriate for your sample preparation (i.e. different column, mobile phase, etc).
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