Polymers, whose polarity is lower than that of DMF are adsorbed by the packing materials of the GPC KD-800 columns. For such polymers, the use of the OHpak SB-800 HQ columns is recommended because their packing material has a weaker hydrophobic interaction than that of the KD-800 columns. Generally, in DMF eluent some salts like LiBr should be added for the SEC analysis of polymers having ionic groups. Salt is added to prevent ionic interaction between sample and packing material.
Sample : Poly(-N,N-dimethylaminomethyl styrene)
Columns : Shodex GPC KD-804 + KD-802.5, OHpak SB-805 HQ + SB-802.5 HQ (8.0mmI.D. x 300mm each) Eluent : 5mM LiBr in DMF Flow rate : 1.0mL/min Detector : Shodex RI Column temp. : 40