Research shows that with furfural concentration increase in a reactionary mix the size of exchange capacity and swelling capacity of anion-exchange resin
DE-53 cellulose anion-exchange resin
was obtained from Whatman (Fairfield, NJ; cat.
During the process, cations are replaced with hydrogen ions using cation-exchange resins; anions are replaced with hydroxyls using anion-exchange resins
. The hydrogen ions and hydroxyls recombine producing water molecules.
Ion exchange is attractive because the perchlorate group has a very high affinity for common polystyrene strong-base anion-exchange resins
. However, recharging the ion-exchange resin is difficult and expensive.
Other qualitative and quantitative methods have been reported (11-14), many of which include prepurification of PBG with anion-exchange resins
, but all rely on the derivatization of PBG with Ehrlich-type reagent, which is not specific for PBG, and thus have the potential for false positives.